text:
Britain's nuclear secrets: inside Sellafield
Redressing scientific publishing
Slippery and never wet
"Boiling the vacuum"
Miazma: physics edutainment
Volume 47 • number 5&6
European Union countries price:
104€ per year (VAT not included)
Britain's nuclear secrets: inside Sellafield
Redressing scientific publishing
Slippery and never wet
"Boiling the vacuum"
Miazma: physics edutainment
Volume 47 • number 5&6
European Union countries price:
104€ per year (VAT not included)
Cover picture: Frame from a simulation of the merger of two black holes and the
resulting emission of gravitational radiation (colored fields, which represent a
component of the curvature of space-time). The yellow areas near the black holes
do not correspond to physical structures but generally indicate where the strong
non-linear gravitational-field interactions are in play. ©Credit: NASA/C. Henze
See P.18 Gravitational Physics: the birth of a new era.
03 Working together on the evidence base | R. Voss
m PAGE 30
and never wet
04 EPS Historic Sites: NatLab, Eindhoven, The Netherlands
06 EPS gears up for 50 th Anniversary
08 Nobel prize in physics 2017
09 In memoriam Prof. Alfred Zawadowski
10 The remake of an iconic photo
11 International conference on Strangeness in Quark Matter in Utrecht
m PAGE 34
"Boiling the vacuum":
in silico plasmas under
extreme conditions
12 Controlling negative ions in plasma using tailored voltage
A Fokker-Planck Model for Wealth Inequality Dynamics
13 Magnetite or maghemite? There is a simple answer
Best tactical approach to handling patients with simultaneous parasitic and HIV infection
14 Highway traffic fluctuations impact congestion durations
Like a game of 'spot the difference' for disease-prone versus healthy people
15 Robustness of states at topological insulator interfaces
The secret to improving liquid crystal's mechanical performance
16 Information stored in quantum states of water fragments
Astronauts to bring asteroid back into lunar orbit
17 Monodisperse magnetic nanoparticles prepared from block copolymer template
First aid kit in some living organisms helps fix DNA after lengthy sun exposure
m PAGE 42
Miazma: physics
edutainment through
a computer game
18 Gravitational Physics: the birth of a new era | M. Sakellariadou
21 Britain's nuclear secrets: inside Sellafield | A. Marino
25 Redressing the inverted pyramid of scientific publishing | J.-S. Caux
29 Physics in daily life: fascinating friction | L.J.F. Hermans
30 Slippery and never wet | M. Backholm, J.V. I. Timonen and R.H.A. Ras
34 "Boiling the vacuum": in silico plasmas under extreme conditions | L.O. Silva
38 A Tribute to Manne Siegbahn | H. Kubbinga
42 Miazma: physics edutainment through a computer game | Zs. Fülöp, S. Biri and G. Lévai
47 Annual index volume 48 - 2017
Working together
on the evidence base
To become a credible actor on the stage of science policy,
the EPS needs to invest in its evidence base, with the strong
support from Divisions and Groups
Not different from other
learned societies, the EPS
has since long organised
itself in Divisions, Sections and
Groups to federate its members, aggregate
their expertise, and promote
Europe-wide actions and initiatives
in different areas of our science.
Traditionally, the structure of EPS
Divisions, and of divisional Sections,
has followed the development of
important branches of contemporary
physics – the arrival of the new
kid on the block, the Gravitational
Physics Division, has been rapidly
catalysed by the recent discovery
of gravitational waves. In a complementary
approach, EPS Groups
have been mostly concerned with
cross-cutting issues, activities and
technologies such as the history
of physics, accelerators, and physics
for development. The excellent
work of the Divisions and Groups
is the scientific and social lifeblood
of our society, and our most visible
figurehead in the scientific community.
Divisions and Groups are
instrumental in promoting open scientific
communication, networking,
and international collaboration; they
organize many of the most important
conferences in our field, often
drawing a global audience; through
a series of prestigious prizes, they
reward research excellence, raise
the visibility of young talent, and
promote diversity.
To safeguard the future of physics
education and physics research,
the EPS must not only serve the immediate
scientific and professional
interests of its members, and their
organisational needs. In a long-term
vision, our society needs to invest
in the areas of science policy, outreach,
and communication, to act as
the central voice of European physics,
and as a credible and efficient
representative of our community
vis-à-vis political and institutional
decision makers, the media, and
the public. This insight is neither
new nor is it original. Several years
ago, the EPS has started to develop
structures and actions to raise its
science policy profile, epitomised
by the development of a point of
presence in Brussels and supported
by the creation of a high-level
Advisory Board on Science Policy.
However, structures need to be
filled with contents, and action and
communication must be based on
reliable facts and robust arguments.
To this end, the EPS must invest in
its evidence base. A successful example
from the recent past is the
study "The importance of physics to
the economies of Europe" published
in 2012 which was well received,
but starts to become obsolete and
needs to be updated. An example
of a different, equally urgent project
is a study of high-school physics
teaching in Europe, which is of
strategic importance for attracting
talent, and for promoting awareness
of the importance of physics
for our society. The recent review
"Nuclear physics for cultural heritage"
published by the EPS Nuclear
Physics Division sets an excellent
example for topical reports which
of the
evidence base
is an excellent
for the
Sections and
Groups to join
forces and to
team up with
all instances
of the EPS
together for a
common goal.
highlight the relevance of physics
research and physical methods for
other branches of science, and for
everybody's daily life.
The backbone of the EPS evidence
base will be the framing document
"Grand challenges on the Horizon
2050" which is presently under development,
designed to address both
the scientific and the societal challenges
which physics is expected to
face between today and the middle
of the twenty-first century. This paper
will not only develop a strategic
vision for fundamental and applied
research for several decades. Equally
important, it will serve as the foundation
and fil rouge of future actions
and initiatives in the science policy
arena. For this ambitious project to
succeed, we need to harness the full
bandwidth of scientific expertise
and technological know-how which
the EPS represents. Nobody is better
placed to deliver this expertise
than our Divisions and Groups, and
each of them will be called upon to
contribute to this unique endeavour.
The development of the evidence
base is an excellent opportunity for
the Divisions, Sections and Groups
to join forces and to team up with
all instances of the EPS governance,
working together for a common
goal. It will be an equally unique opportunity
to take both collaboration
inside the Society and our visibility
to the outside to a higher, even more
rewarding level. n
llRüdiger Voss,
EPS President
2017 • Volume 48 • number 5 & 6
Europhysics news is the magazine of the European
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Legal deposit: October 2017
Eindhoven, The Netherlands
Nothing ventured, nothing gained
On October 5, 2017, NatLab in Eindhoven was
inaugurated as EPS Historic Site with 80 guests
from all venues in society joining the festivities.
The entrepreneurs Anton and Gerard Philips
founded this industrial laboratory in 1914.
Their goal was to improve the production of
incandescent lighting, both by fundamental and
applied research in physics and engineering.
In view of the turmoil in Europe in 1914, this was a highly visionary and
daring activity. While the emperors, kings, prime ministers and a single
czar were busy as ego-driven warmongers, the industrialists acted as
Europeans 'avant la lettre' by their travels to Moscow and all other places
to sell their lighting systems.
NatLab – short for Natuurkundig Laboratorium, i.e. Physical Laboratory –
developed into a powerhouse of excellent research. Both the unprecedented
freedom in choosing the research themes as well as the policy of
inviting university physicists to NatLab (e.g. Albert Einstein) are at the
basis of the fame and scientific standing of this institution. A comparison
to Bell Labs of ATT 1 and the labs of GE is appropriate, although the former
has the extra achievement of having nurtured 13 Nobel Prize winners
such as Bardeen, Brattain, and Shockley in 1956 for their discovery of
the transistor effect.
At the beginning of the 20 th century, physics research in The Netherlands
was rather academic, with small research groups consisting of a
single professor with very limited academic and technical support. The
exception to this rule was the group of Heike Kamerlingh Onnes in Leiden,
working on the liquefaction of gases including helium. The experimental
infrastructure demanded support of technicians, operators, and a large
group of young scientists engaged in the experiment: the first 'big physics'
venture in the Netherlands. One of these young experimental scientists
was Gilles Holst, who was selected by the Philips brothers to help them
'From harmony to chaos', J. de Heer and K. Tazelaar (publisher 1001, Amsterdam, 2013)
EPS Historic sites
m View of entrance of NatLab, showing the protruding auditorium and the two 'pillars of science'.
in setting up the embryonic NatLab
in 1914 with only a few employees.
In 1923 the building of the current
Historic Site at Kastanjelaan 500 in
Eindhoven was opened. It was used
for this purpose until 1963, when the
research facilities were moved to a new
site in Waalre.
It is interesting to realize that the
1914 connection between Leiden and
Eindhoven in experimental research
has been reestablished. As of 2017,
NatLab and The Kamerlingh Onnes
Laboratory/Lorentz-Institute are the
only two EPS Historic Sites in the
Netherlands. Planning or coincidence,
who knows?
In 2003, the Waalre site of Philips
Nat Lab has evolved into High Tech
Campus Eindhoven 2,3 , a research
community where sharing results is
the game. This initiative again has a
visionary character, with a large group
of small and large companies (including
Philips) engaged in innovation. In
2012, High Tech Campus Eindhoven
was sold to an investor who manages
the site, with Philips leasing its buildings
just as the other parties.
The inauguration on October 5,
2017, was a lively affair, with guests
ranging from former directors of
NatLab to representatives of local and
national high-tech companies, including
the spinouts such as ASML, FEI,
NXP and Philips Lighting, as the most
recent chick that has left the nest. Politics,
culture, family of Philips luminaries
and even a grandson of Anton
Philips also joined in.
Excellent talks by prof. Dirk van
Delft, director of Museum Boerhaave
in Leiden, and dr. Henk van Houten,
CTO Royal Philips, discussed the past
and future research of Royal Philips.
EPS President Rüdiger Voss unveiled
the memorial plate, together with
past President Chris Rossel. The latter
memorized that NatLab now is the
second industrial lab that is honored
as Historic Site, the other being IBM
labs in Zurich since September 2017.
At lunch the guests enjoyed a preview
of the reconfigured 'Le Poème
Électronique' as shown at the Philips
Pavilion at Expo 58 in Brussels. This
version differs in such from the Expo
58 show that the visual material is
much closer to the original ideas of
Le Corbusier. In a clash between art
and company culture at Philips, the
latter emerged as the winning party 4 .
The memorial plate at NatLab is
located on a pillar supporting the
auditorium where all famous visitors
held their talks: a 'pillar of science'.
In the Netherlands we are proud of
NatLab, which lies at the basis of the
current position of the Eindhoven
region as a kingpin in the role of The
Netherlands as the Silicon Valley of
the European Union. For the Netherlands,
the annual contribution to the
EU equals approximately 1% of the
economic damages suffered during
WW II. This is a very low insurance
premium for avoiding war in Europe
during 72 years! 'Make love, not war'
can be paraphrased as 'do physics, stop
quarrelling'. Join forces, think of the
success of CERN. n
llHerman C. W. Beijerinck
emeritus professor Eindhoven
University of Technology
. Memorial plate with text (b/w) embedded in listing of other Historic Sites (grey), mounted on 'pillar of science'.
Left to right: Pauline Terreehorst (director NatLab/Plaza Futura cultural centre), Rüdiger Voss (President EPS),
Anton Philips (grandson of entrepreneur/founder Anton Philips), and Henk van Houten (CTO Royal Philips).
50 Years of EPS
EPS gears up
for 50 th Anniversary
In 2018, the European Physical Society will celebrate its 50 th anniversary. From its
founding in Geneva, through the move to Mulhouse and now to the involvement of the
EPS in the science policy debate in Europe, the EPS will organise a series of special
events highlighting the contributions of EPS members over the past 5 decades.
special logo will be used
in 2018 on all official EPS
documents. It symbolizes
the deformation of the spacetime by
a mass according to Einstein's general
relativity theory. The presence of
planets, stars and galaxies deform the
fabric of spacetime like a large ball
deforms a bedsheet. The logo is also
a reference to our new Gravitational
Physics Division.
A special session will be organised
at the EPS Council meeting in Paris on
7 April 2018.
We are looking for a speaker that
can summarise the 50 years of EPS,
an entertaining speaker on physics in
m The special logo that will be used in 2018 on all official EPS documents.
everyday life, and a speaker on perspectives
in physics.
The EPS was founded at the University
of Geneva and a special session is
planned on 28 September 2018 in the
Aula Magna, where the first EPS General
Meeting took place. This session
will be devoted to remembering those
who have contributed significantly to
the EPS, and the main achievements in
physics over the past 50 years.
Much has happened over the past
50 years in physics research and development,
as well as in society at large.
These events have had an impact on
the EPS. A special booklet, outlining
the major events in the developments
m Some of the pictures already collected
on the photo archive.
50 Years of EPS NEWS
of the EPS is currently being prepared.
It will look at how changes in society
and policy have influenced the EPS.
The EPS Young Minds sections will
be organising a photo competition. It
is open to everyone to show research
and education in physics. The rules are
given in the box.
Panels to be used as the basis for an
exhibit "Physics in Your Life" are also
under preparation. The panels will describe
various physical phenomena in
a colourful and engaging manner. The
style will be loosely based on "Physics
in Daily Life", the popular column
written by J. Hermans that appears in
EuroPhysics News.
The EPS is inviting all EPS Member
Societies and Divisions and groups
to sponsor a speaker at one of their
events in 2018.
Finally, a document and photo archive
to collect as much material about
the EPS and its history has been set
up. You are invited to contribute at:
http://bit.ly/2zxonLL n
l l David Lee
EPS secretary General
Within the 50 th anniversary of the European
Physical Society (EPS), the photo
contest EPS – 50years&counting is
launched. The theme is the celebration
of EPS 50 anniversary. Feel free to take
pictures of your lab and your colleagues,
of your data analysis or your latest setup,
but don't forget to add something
that recalls the 50 th anniversary.
EPS – 50years&counting is sponsored
by the European Physical Society (EPS).
• The contest is open to all, professional
and amateur, regardless of age,
gender or nationality.
• Only individuals who have reached the
age of majority in their jurisdiction of
residence at the time of entry can apply.
• The contest is open to members of the
EPS or one of its Member Societies
• Submissions must be in digital format.
The pictures must be uploaded on
contest or sent via email to secretariat@
eps.org. All digital files must be 20 megabytes
or smaller, in JPEG or .jpg format,
and must be at least 1,600 pixels wide (if
a horizontal image) or 1,600 pixels tall (if
a vertical image). Each participant can
upload up to three pictures.
• The deadline for the submission is 31
January 2018.
• After deadline, all the pictures will be
uploaded by the contest organizers
in a specific Facebook album on EPS
Facebook page.
• Both colour and monochrome images
will be accepted.
• The participant has to provide: caption,
name, last name, email address,
telephone contact and geo-references
of the photo (where it was taken).
• The submission must not contain
obscene, provocative, defamatory,
sexually explicit, or otherwise objectionable
or inappropriate content.
• Each image submitted must be the
original and unpublished work of
the participant who must also be its
copyright owner.
• The participant shall retain copyright to
the image entered for the competition.
• By submitting an image for the
competition, the participant will
be regarded as having granted the
organiser the right to use the image
in print, broadcast and/or electronic
media without any fee payment.
• Images received by the organiser
through the competition will not be
used by the organiser for commercial
• The top 3 photos will be selected by a
panel of judges and their decision is
final. No correspondence pertaining
to the selection process and decision
will be entertained.
• The People's choice award will be granted
to the picture with the largest number
of "Likes" collected on Facebook.
• Images will be judged based on Artistic/visual
appeal, originality, creativity
and relevance to the theme.
• Results of the competition will be
posted on EPS website page. The
winners will be also notified via
email, by the end of March 2018.
The top 3 photos plus the People's
choice photo will receive a prize of
200€ and an invitation to the 50 th anniversary
ceremony of EPS.
The award ceremony and the final
exhibition will be held during the
50 th anniversary ceremony of EPS
planned for 28 September 2018 in Geneva
(CH). The first 10 best images selected
by the technical jury will be printed in
20 × 30 format and displayed during the
ceremony. n
Nobel prize in physics 2017
Nobel prize in physics 2017
On September 14, 2015 the two detectors of the Laser Interferometer Gravitational-Wave
Observatory (LIGO), located in Hanford (Washington) and Livingston (Louisiana)
in the United States, observed a transient gravitational-wave signal, called the GW150914.
This is the first direct detection of
gravitational waves, accomplished a
century after the theoretical prediction
of Albert Einstein as a consequence of
his theory of general relativity. This decisive
detection was the result of an international
effort that lasted several decades and involved
more than one thousand scientists
and engineers.
Albert Einstein, only one year after formulating
his theory of general relativity, had
realised that in the weak-field regime, the
linearised field equations admit transverse
wave solutions travelling at the speed of
light. He called these solutions gravitational
waves. Yet the question of their existence as
solutions of the fully nonlinear field equations
hunted Einstein until the end of his
life. The debate on the reality of gravitational
waves lasted several decades and was only
resolved in January 1957 during the Chapel
Hill conference on "The Role of Gravitation
in Physics" – known today as the GR1 meeting
– during which Felix Pirani proposed
a brilliant deduction on how to "measure"
gravitational waves. One year earlier, in
1956, Felix Pirani had published an article
entitled "On the physical significance of the
Riemann tensor", showing that gravitational
waves manifest themselves as fluctuating
tidal forces on masses within their path. In
this work, Felix Pirani highlights the interpretation
of geodesic deviation and its relation
to the curvature tensor.
The first gravitational wave detector was
developed in the sixties by Joseph Weber, one
of the attendees of the Chapel Hill conference.
The device he designed and subsequently
built, consisted of massive aluminium cylinders
–"antennas" – vibrating at a resonance
frequency. The principle of these resonance
detectors, called "Weber bars", is based on the
effect of gravitational waves on the fundamental
resonant mode of aluminium bars
at room temperature. By the seventies, there
were developed aluminium bar systems operated
at and below the temperature of liquid
helium, to reduce thermal noise. However,
despite several efforts, gravitational waves
were not detected.
Hopes were soon raised again with the
discovery of the binary pulsar system PSR
B1913+16 by Hulse and Taylor in 1974 – recipients
of the 1993 Nobel Prize in Physics –
and the subsequent observations of its energy
loss by Taylor and Weisberg. This discovery
provided the first demonstration of the existence
– not direct detection – of gravitational
waves, leading the hunting for gravitational
waves into a new phase.
The most promising design of gravitational
wave detectors is laser interferometry
offering a way of measuring the motion of
widely separated test masses freely suspended
as pendulums, produced as they interact with
a gravitational wave. In the seventies, Rainer
(Rai) Weiss – MIT— conceived the idea of
building such a laser interferometer, and by
late seventies he experimented with a modest
prototype whose two L-shaped "arms" were
1.5 m long. The progress was then rapid. By
1983 Ronald Drever – Caltech – had already
built an interferometer whose "arms" measured
40 m. The LIGO project saw the light in
the eighties as a Caltech-MIT project funded
by NSF; it was originally led by Kip Thorne,
Rainer Weiss and Ronald Drever. In 1994
Barry Clark Barish, an experimental physicist
– expert in high energy physics with
experience in managing large projects – was
appointed as the LIGO administrative leader.
Barry Barish transformed the Caltech-MIT
project into an international collaboration,
the LIGO Scientific Collaboration (LSC), that
includes today over 1200 people. Barish's vision
was to build the LIGO as an evolutionary
laboratory. By the early 2000s, TAMA 300 in
Japan, GEO 600 in Germany, LIGO in the
United States, and Virgo in Italy were completed.
Combinations of these detectors made
joint observations already from 2002.
The initial LIGO, 2002-2010, did not detect
any gravitational waves. The upgrade lasted
five years and the advanced LIGO (aLIGO)
started in February 2015. On the 14 th September
2015, four days before the aLIGO starts its
official run, the two interferometers detected a
burst of gravitational waves from the collision
of two giant black holes. In a far galaxy, 1.3
billion years ago, two black holes, of 29 and 36
solar masses, orbiting closer and closer to each
other, collided and merged into a single black
hole of 62 solar masses, releasing an enormous
amount of energy, equivalent of an energy of
3 solar masses times the speed-of-light
squared. LIGO had fulfilled its scope and the
efforts of Rai Weiss, Kip Thorne and Barry
Barish had paid off. The era of Gravitational
Astronomy has now begun. Two more detections,
the GW151226 and the GW170104,
and a lower significance candidate, the
LVT151012 have followed. The Advanced Virgo
joined the Advanced LIGO twin interferometers
on August 1, 2017. Soon afterwards,
on August 12, 2017 the Advanced Virgo and
the two Advanced LIGO detectors observed
gravitational waves from a binary black hole
coalescence. This is the first three-detectors
observation, called GW170814, observed first
at the LIGO Livingston and then at the LIGO
Hanford and Virgo detectors, with a delay of
respectively around 8 ms and 14 ms. Other
detectors are planned to join the network:
KAGRA is being built in Japan, and LIGO
India has been recently approved. European
Space Agency has selected the space-based
laser interferometer, LISA, for its third large
class mission, due for launch in 2034. There
are also plans for the third-generation gravitational-wave,
such as the Einstein Telescope
or the Cosmic Explorer.
On the 3 rd October 2017, the Royal Swedish
Academy of Sciences has decided to award the
Nobel Prize in Physics 2017, one half to Rai
Weiss and the other half jointly to Barry C.
Barish and Kip S. Thorne – all three members
of the LIGO/VIRGO Collaboration – "for decisive
contributions to the LIGO detector and
the observation of gravitational waves". The
Nobel Prize acknowledges the efforts of a
whole community during 45 years and the
decisive contribution, vision and dedication
of Barry Barish, Kip Thorne and Rai Weiss.
The years to come gravitational waves
are expected to be detected from a variety of
sources. Such detections will help us to better
understand our universe and test the validity
of our theories.
llMairi Sakellariadou
In memoriam
Prof. Alfred Zawadowski
One of the best known Hungarian physicists of our times, Prof. Alfred Zawadowski,
– or as everybody in the international physics community knew him, 'Fred' – a former
president of the Roland Eötvös Physical Society, the Hungarian member society
of EPS, passed away on August 5 th , 2017 in Budapest, at the age of 81.
The role played by the EPS Budapest
Office for the exchanges and communication
between physicists
from East and West in Europe is well known.
Fred Zawadowski was a prominent
member of our physics community, who
played a major role in sustaining research
excellence in Central Europe in communist
times. Fred was born in 1936 in Budapest.
He excelled in mathematics and physics already
in his high-school years, and enrolled
at the Roland Eötvös University in 1954 as
a physics major. When getting his diploma
in 1959, as the best student in his class he
might have hoped ‒ under normal conditions
‒ to get a position at the university
to work on field theory, his favourite subject.
The late fifties of the last century were,
however, not a normal period in Hungary.
After the repression of the revolution in
1956, Fred had to accept a position at the
Institute for Technical Physics of the Academy
of Sciences to work on semiconductors.
It was there that he became interested in the
application of field-theoretical methods to
solid-state physics problems.
A few years later, when the political
climate got milder, he could move to the
Central Research Institute for Physics of
the Academy, where he got more liberty
to choose his research subjects, and, at the
same time, he was allowed to teach modern
solid state physics at the Eötvös University.
This gave him the opportunity to
start to build up around himself a group of
physicists, consisting of both theorists and
Fred Zawadowski had a broad research
interest. His first breakthrough was the
application of the idea of field theoretical
renormalization group to the Kondo problem,
much before Wilson's work. Indeed,
throughout his life, he was passionately
interested in the Kondo problem, and returned
to it later on several occasions. He
studied it in alloys, mesoscopic structures,
in the context of molecular electronics, in
metallic glasses, and wrote ‒ together with
George Grüner ‒ a well-known review paper
on the subject. But he created many important
contributions in the field of correlated
systems, superconductors, and one-dimensional
systems, too. In a famous work with
George Grüner and Paul Chaikin he gave
a simple description of the dynamics and
noise generation in charge-density wave
systems. With his works on two-level systems
and tunnelling centres in metallic
glasses he established a new direction in
this field, and his review on multichannel
Kondo systems, written together with Daniel
Cox, is a cornerstone reference today.
Fred Zawadowski was part of a lively, international
network of fellow physicists. He
was welcome everywhere because he was
an equal partner in scientific discussions
to people like Elihu Abrahams, Phil Anderson,
John Bardeen, Patrick Lee, Philippe
Nozières or David Pines, just to name a
few. He has spent several years at various
places in the United States including Charlottesville
(Virginia), Rutgers, UCLA and
Urbana-Champaign. In Europe, he had
extended stays at the ILL in Grenoble, and
in Munich as the winner of the prestigious
Humboldt Award.
One of Fred Zawadowski's major
achievements was, however, not merely a
scientific contribution, but the creation of
a European-level Institute of Physics at the
Budapest University of Technology and
Economics. Although he remained a theorist
throughout his life, he always liked to
talk to experimentalists and tried to gather
theorists and experimentalists around
common subjects. He felt that it was his
duty to strongly support young promising
people. He was especially successful in this
endeavour, when ‒ in the early nineties ‒ he
got the possibility to reorganize completely
the Institute of Physics of the Budapest
University of Technology. He created a new
and by now worldwide recognized institute
with a strong and very successful physics
program and PhD school, and with remarkable
achievements in the field of statistical
and condensed matter physics and optics,
both in theory and experiment.
Fred Zawadowski's demise is a tragic loss
to the Hungarian and international physics
community. His person will be remembered
and his legacy in physics will be preserved. n
llJenő Sólyom
Wigner Research Centre for Physics,
and Roland Eötvös University, Budapest
llGergely Zaránd
Budapest University of Technology
The remake of an iconic photo
This year's 103 rd Congress of the Italian
Physical Society (SIF), which
celebrated the 120 th anniversary
of the society, has just ended. Since its first
edition in 1947 after WW2 on the occasion
of the 50 th anniversary of the SIF, the Congress
(numbered as 33 rd in order to follow
the numeration of previous assemblies and
meetings which had taken place since the
foundation of the SIF in 1897) has been
touring around Italy in various universities.
The Congress took place in Trento.
This is an ancient and beautiful city in
the northeast of Italy, very lively from the
physics point of view, housing the Physics
Department of the University, the Trento
Institute for Fundamental Physics and
Applications of the Italian
National Institute of Nuclear
Physics (TIFPA-INFN),
the Centre for Materials and
Microsystems of the Bruno
Kessler Foundation (CMM-
FBK), the European Centre
for Theoretical Studies in
Nuclear Physics and Related
Areas (ECT*), the Bose-Einstein
Condensation Centre of
the Italian National Institute
of Optics of the National Research
Council (BEC-CNR
INO@UniTn), the Centre for
Neuroscience and Cognitive
Systems of the Italian Institute
of Technology (CNCS-IIT@
UniTn), and in addition a very
attractive and renowned Science
Museum (MUSE).
The Congress by itself has been extremely
interesting, with outstanding plenary talks as
well as many invited talks and communications
in the seven parallel sessions covering
all branches of physics, namely: Nuclear
and Subnuclear Physics; Solid State Physics;
Astrophysics; Geophysics and Physics of
the Environment; Biophysics and Medical
Physics; Applied Physics, Accelerator Physics
and Physics for Cultural Heritage; Physics
Education and History of Physics.
But this year's Congress has been very
special because of the commitment and
determination that the physicists of Trento
have shown – with enormous success –
to make their city part of the presence of
hundreds of scientists coming from every
corner of Italy and beyond.
The collateral programme of the Congress
was splendidly named "FisiCittà".
The exact translation would be "PhysiCity"
but the jeu de mots is untranslatable
since "fisicità" (with only one t) in Italian
means "physicality". This programme was
unique in its kind with an unprecedently
dense series of events hosted in theatres,
cinemas, museums and cafés, where the
Trento people were able to meet and listen
to a large number of physicists, and interact
directly with them. FisiCittà has had a
tremendous impact, giving maximum visibility
not only to the Congress but to our
entire community.
To celebrate its 120 th anniversary, the SIF
has decided to organize the usual round table
of the Congress, which normally focuses
on a theme related to "Physics and Society",
on the issue of women and scientific vocations.
This round table, "Physics, feminine
singular", attended by six distinguished
women colleagues, was coupled to a second
round table, "Research: Which spaces
for women?", this time in the context of FisiCittà,
where personalities from the world
of research, university, school and politics
could express their views.
On the heels of these two events, the
Communication Office of Trento University
had the brilliant idea of immortalising 28
female speakers of the Congress, of different
ages and fields of our discipline, together
with only one among their male colleagues
(Guido Tonelli, one of the discoverers of the
Higgs boson at CERN), in a remake of the
famous photo of the 1927 Solvay Conference
which 90 years ago marked the birth of
quantum physics. Not anymore 28 men and
one woman, but the exact opposite.
The picture, taken almost for fun, had
however an unexpected resonance, on all
media and even on national television networks.
I am very happy of
such a resonance since it
put everyone's eyes on the
importance of women in
physics and in scientific research.
As far as I am concerned,
I am very proud to
be in that photo!
What came out? A
provocation, of course,
but something to seriously
think about. The image
triggers a pungent, stimulating
reflection: from
Madame Curie's time,
much has been done to
increase women's presence
and careers in science. But
unfortunately not enough,
the road is still long ahead.
Meanwhile, let me say to my women friends
and colleagues: don't fear science, don't be
afraid to choose a scientific career, you have
all the right credentials to do it. And Antigone
Marino, a young physicist at Federico
II University in Naples, former chairwoman
of the Young Minds Committee of the European
Physical Society, sitting in the picture
in place of Albert Einstein, embodies
the hope that things will change soon. n
llLuisa Cifarelli
Italian Physical Society, President
International conference on
Strangeness in Quark Matter in Utrecht
The 17 th edition of the International
Conference on Strangeness in Quark
Matter took place from 10-15 July
2017 in Utrecht in the Netherlands (http://
sqm2017.nl). This conference series focuses
on new experimental and theoretical developments
on the role of strangeness and
heavy-flavour production in heavy-ion collisions,
and in astrophysical phenomena related
to strangeness. This year's conference
attracted more than 210 participants from
25 countries, with 20% of female researchers.
A two-day long graduate school on the
role of strangeness in heavy ion collisions
with 40 young participants preceded the
conference, which was supported by the
Dutch Physical Society (NNV).
The scientific programme consisted of
53 invited plenary talks, 70 contributed
parallel talks and a poster session. Three
discussion sessions provided scope for the
necessary debates on crucial observables to
characterise strongly interacting matter at
extreme conditions of high baryon density
and high temperature and to define possible
future directions. One of the discussions
centred on hadronic resonance production
and their vital interactions in the partonic
and hadronic phase that provide evidence
for an extended hadronic lifetime even in
small collision systems and might affect
other observables for the quark-gluon
plasma. Moreover, future astrophysical
consequences for SQM following the recent
detection of gravitational waves were
outlined: gravitational waves from relativistic
neutron star collisions can serve as
cosmic messengers for the phase structure
and equation-of-state of dense and strange
matter, quite similar to the environment
created in relativistic heavy-ion collisions.
Representatives from all major collaborations
at the Large Hadron Collider (LHC)
and Super Proton Synchrotron at CERN,
Brookhaven's Relativistic Heavy Ion Collider
(RHIC), and the Heavy Ion Synchrotron
SIS at the GSI Helmholtz Centre in Germany
made special efforts to release new data
at this conference. Thanks to the excellent
m More than 210 participants attended 2017 SQM in Utrecht. [image credit: Pieter van Dorp van Vliet, Utrecht University]
performance of these accelerator facilities
and detectors, a wealth of new data on the
production of strangeness and heavy flavour
in nuclear collisions has become available.
Among the highlights presented at the
conference, the ALICE Collaboration reported
new results on strange and multi-strange
hyperon production in 5.02 TeV
heavy-ion collisions and the first measurement
of charm baryons (Λ c and Ξ c )
in proton-proton and proton-lead collisions
at the LHC. Furthermore, ALICE
performed the most precise measurement
of the (anti-)hypertriton lifetime, an exotic
nucleus composed of a proton, a neutron
and a lambda particle. The CMS Collaboration
reported progress in understanding
the energy loss of charm and beauty quarks
in the hot QCD medium, while the STAR
experiment at RHIC gave an update on
global lambda polarisation, which reveals
that the curl of the fluid created at RHIC is
much higher than that in any fluid ever observed.
Enhanced strangeness production
in small systems, as reported by the HADES,
NA61/SHINE and ALICE Collaborations,
has also reignited the discussion surrounding
strangeness production as a signature
of the quark-gluon plasma.
Experimentally, the field faces high
prospects for future measurements at the
Facility for Antiproton and Ion Research
in Darmstadt, NICA at JINR Dubna, and
at CERN (namely detector upgrades at the
LHC during long shutdown 2 and the AF-
TER programme).
On the theory side, new developments
and vigorous research efforts are taking
place towards a full understanding of
strangeness production and open heavy-flavour
dynamics in heavy-ion collisions.
Global polarisation in heavy-ion collisions
is also a highly debated topic since it allows
studying the vorticity of the medium and
the initial magnetic field.
Four young scientist prizes, sponsored
by the European Physical Journal A, were
awarded to the best parallel talk and poster
presenters: Heidi Schuldes (Goethe University
Frankfurt, Germany), Christian
Bierlich (Lund University, Sweden), Yingru
Xu (Duke University, US) and Vojtech
Pacik (Niels Bohr Institute, Denmark).
The next edition of the SQM conference
will take place in Bari, Italy, in June 2019. n
llAndré Mischke
conference chair
Highlights from European journals
Controlling negative ions in
plasma using tailored voltage
Plasma processing of materials has wide applications in science
and industry. In a capacitively coupled plasma, a feedstock gas,
often diluted with hydrogen, is partially ionized with an electric
discharge. In the most basic configuration, the key plasma parameters
of ion flux and ion energy are strongly linked: increasing
the applied sinusoidal voltage amplitude increases both.
With a multiple harmonics waveform, it is possible to decouple
ion flux and energy, obtaining increased processing speed
while maintaining the ideal ion energy for surface reactions.
This concept has been formulated and exploited for positive
ions. Hydrogen plasmas, however, produce also negative ions
which are important in other applications like heating systems
in nuclear fusion.
. Calculated profile of negative ions for different voltage waveforms.
The authors investigated, using a comprehensive numerical
model, the effect of tailored voltage waveforms on the
location, peak density and dynamics of negative hydrogen
ions and the influence of molecular physics on their production
rate. They found that under appropriate conditions it is
possible to concentrate negative ions in a desired position.
This is due to a complex interplay between plasma electrical
quantities, particle energy distributions and transport
phenomena. n
llP. Diomede, B. Bruneau, S. Longo, E. Johnson
and J.-P. Booth,
'Capacitively coupled hydrogen plasmas sustained
by tailored voltage waveforms: vibrational kinetics
and negative ions control', Plasma Sources Sci. Technol. 26,
075007 (2017)
A Fokker-Planck Model for
Wealth Inequality Dynamics
The growing wealth inequality in most western countries during
the past several decades led to an increased interest in
the nature of wealth inequality dynamics – particularly, what
has driven wealth inequality upwards? Statistical mechanics
can be used for addressing this question. We present a simple
stochastic model for wealth and income and derive from it a
Fokker-Planck equation – a standard tool in non-equilibrium
statistical mechanics for studying the evolution of a distribution.
Using this equation we are able to calculate the joint wealth-income
distribution and its dynamics.
. Model comparison with data. Overall trend is well captured as well as some
short-term details.
from european journals
Our analysis supports empirical findings on the dynamics of
wealth inequality. We find that wealth inequality inevitably
tends to increase in the long run. However, even if inequality
eventually goes up, we find a criterion for its possible short run
decrease. This criterion is most likely to be fulfilled if the correlation
between wealth and income is very low. The conditions
for such a decrease are found to be met at several points during
the 20 th century, coinciding indeed with an observed decrease
in wealth inequality. n
l lY. Berman, Y. Shapira and M. Schwartz,
'A Fokker-Planck model for wealth inequality dynamics',
well suited to nanomaterials, is simple and straightforward, and
as long as appropriate measures and protocols are observed
– all of which are explained in the paper – even inexperienced
users will find little difficulty in its implementation. n
llJ. Fock, L. K. Bogart, D. González-Alonso,
J. I. Espeso, M. F. Hansen, M. Varón, C. Frandsen
and Q. A. Pankhurst
'On the 'centre of gravity' method for measuring the
composition of magnetite/ maghemite mixtures, or the
stoichiometry of magnetite-maghemite solid solutions,
via 57 Fe Mössbauer spectroscopy', J. Phys. D: Appl. Phys. 50,
265005 (2017)
Magnetite or maghemite?
There is a simple answer
Best tactical approach to
handling patients with simultaneous
parasitic and HIV infection
New mathematical model for cryptosporidiosis - HIV
co-infection explores their synergistic relationship
in connection with prevention and treatment.
One of the most common waterborne diseases worldwide is
cryptosporidiosis, a parasitic disease affecting the small intestine
and possibly our airways. It is a common cause of diarrhoea
in HIV-positive patients, who are known to have lower
. Cryptosporidiosis. Credit: 2012 Michael Bonert. CC BY-SA 3.0.
m Correlation between δ RT , the 'centre of gravity' of the room temperature 57 Fe
Mössbauer spectrum of a magnetite/maghemite sample vs. the fraction of 57 Fe
atoms present in magnetite, α.
The composition or stoichiometry of magnetite (Fe 3 O 4 ) and
maghemite (γ-Fe 2 O 3 ) mixtures or solid solutions is important
for the physical, geological and material sciences. It is also significant
in biomedical science, where magnetic nanoparticles
are used both in vitro and clinically, and where both ferrous and
ferric iron ions play active roles in the production of reactive
oxygen species. However, the accurate determination of the
composition/stoichiometry can be tricky, as it requires either
well-crystallised samples suitable for x-ray diffraction, or it relies
on chemical dissolution methods that, depending on the nature
of the sample, are often either unfeasible or inappropriate.
However, there is a simple answer, in the form of the recently
proposed 57 Fe Mössbauer spectroscopic 'centre of gravity method'.
The COG method is non-destructive and determines the
composition/stoichiometry from the mean isomer shift, δ RT . It is
from european journals
immunity. Now the authors have developed a new model and
numerical simulations to determine the optimal combination
of prevention and treatment strategies for controlling both
diseases in patients who have been co-infected. Their results,
recently published, show a positive impact on the treatment
and prevention for cryptosporidiosis alone, for HIV-AIDS alone,
or for both together. They found that cryptosporidiosis preventions
and treatment alone had no significant impact on
reducing HIV-AIDS-related problems. By contrast, the prevention
and treatment strategy for HIV-AIDS had a significant positive
impact on the co-infected patients. Finally, applying both
strategies at the same time resulted in reduction in all cases. n
llK.O. Okosun, M.A. Khan, E. Bonyah and
S.T. Ogunlade,
'On the dynamics of HIV-AIDS and cryptosporidiosis',
Eur. Phys. J. Plus 132, 363 (2017)
Highway traffic fluctuations
impact congestion durations
up to several hours. We find that durations of congested traffic
behave in the same way, and we conclude that traffic flow
fluctuations are an important factor in congestion dynamics.
The large number of short-lasting traffic jams implies a large
risk for rear-end collisions. n
llS. M. Krause, L. Habel, Th. Guhr and M. Schreckenberg,
'The importance of antipersistence for traffic jams',
Like a game of 'spot the
difference' for disease-prone
versus healthy people
The change in behaviour of natural nanoparticles, called
lipoproteins, under pressure could provide new insights
to better understand the genesis of high cholesterol
and atherosclerosis.
Understanding common diseases sometimes boils down
to grasping some of their basic mechanisms. For instance,
a specific kind of natural nanoparticles, called low-density
lipoproteins (LDL), are fascinating scientists because their
modification plays a key role in people affected by high
cholesterol. They are also known for their role in the formation
of atherosclerosis. The authors mimicked variations of
LDL found in people affected by such diseases. They then
compared their responses to temperature variations and increased
pressure with those of lipoproteins found in healthy
people. Their findings, recently published, show that the LDL
. Dynamical behaviour of different low-density lipoproteins as a function
of temperature and pressure.
m Traffic flow time series (vehicles per minute) during one day on a highway in
Germany, with two rush hours and strong fluctuations.
Many highways around large cities are running above their
capacity, leading to congested traffic. A useful statistical description
of congestion distinguishes three phases: Free flow,
synchronized traffic and wide moving jams. Traffic breakdown
from free flow becomes increasingly likely around a critical flow
(a certain number of vehicles per minute, specific for the highway
section). Here we investigate the influence of flow fluctuations
on congestion durations. As can be seen in the figure,
traffic flow is antipersistent: It shows large fluctuations on short
time scales which quickly trend back to the mean value, i.e. they
reverse fast. Therefore, the duration of times with a flow above
a critical value (here 60 vehicles per minute) is most oftenly a
few minutes, but sometimes it extends over longer intervals
from european journals
from healthy people behaved differently when subjected
to high pressure compared to LDL affected by the common
diseases studied. The authors found that when LDL particles
were subjected to variations in temperature, their behaviour
was very similar. In fact, a rise in temperature increased their
dynamics at the molecular level. However, when the authors
increased the pressure on LDL particles, they found that their
flexibility actually increased under pressure in healthy people.
By contrast, their flexibility clearly decreased for the two
modified forms mimicking disease states. This difference, the
authors believe, could stem from a slightly different lipid
composition. n
llJ. Peters, N. Martinez, B. Lehofer and R. Prassl,
'Low-density lipoproteins investigated under high hydrostatic
pressure by elastic incoherent neutron scattering',
Eur. Phys. J. E 40, 68 (2017)
two regions are of the same topological phase, there is no
such requirement.
Using a multi-orbital model, it is shown in this study that
conductive states can also emerge at the interface between
two non-trivial topological insulators characterized by opposite
spin Chern numbers, another invariant. In general,
these states are sensitive to disorder. However, it is possible
under some conditions to reduce the effect of disorder, or
even to cancel it. These conditions are clarified. Since analogues
of topological insulators can be presently made with
polaritons, ultracold atomic gases, phononic or photonic
materials, these conclusions should motivate experimental
studies in many directions. n
l lA. Tadjine and Ch. Delerue,
'Robustness of states at the interface between
topological insulators of opposite spin Chern number',
Robustness of states at
topological insulator interfaces
Topological phases of matter are characterized by invariant
numbers. In two-dimensional time-reversal symmetric electronic
systems, a Z 2 valued (0 or 1) invariant distinguishes
trivial insulators from non-trivial ones. Interfaces between
trivial and non-trivial topological insulators are known to
host conductive channels protected against disorder. The
protection of these states originates from the necessity of
a gap closure in order to change topology. However, if the
The secret to improving
liquid crystal's mechanical
Better lubricating properties of lamellar liquid crystals
could stem from changing the mobility of their
structural dislocations by adding nanoparticles.
. Interface states emerging between two topological insulators with opposite
spin Chern numbers.
m 3D plot of the concentration of nanoparticles around a moving edge dislocation
in a smectic A liquid crystal.
By deliberately interrupting the order of materials–by introducing
different atoms in metal or nanoparticles in liquid
crystals–we can induce new qualities. For example, metallic
alloys like duralumin, which is composed of 95% of aluminium
and 5% copper, are usually harder than the pure metals.
from european journals
This is due to an elastic interaction between the defects of
the crystal, called dislocations, and the solute atoms, which
form what are referred to as Cottrell clouds around them. In
such clouds, the concentration of solute atoms is higher than
the mean concentration in the material. In a paper published
recently, the authors have now theoretically calculated the
static and dynamical properties of the Cottrell clouds, which
form around edge dislocations in lamellar liquid crystals of the
smectic A variety decorated with nanoparticles. In this study,
they demonstrate a formula previously used to approximate
the mobility of dislocations in the presence of Cottrell clouds.
They then perform a numerical simulation of the problem
to study how the Cottrell cloud erodes when the dislocation
moves at high speed. This work could be important, for example,
in the context of improving the lubricating performance
of such liquid crystals. n
llP. Oswald and L. Lejček,
'Drag of a Cottrell atmosphere by an edge dislocation in a
smectic-A liquid crystal', Eur. Phys. J. E 40, 84 (2017)
Information stored
in quantum states
of water fragments
Does water have memory? Well, not in the usual sense. But it is
known, that if you tear water molecules apart, the remaining
fragments can tell you a story about how it happened. To investigate
this phenomenon, a plasma reactor producing miniature
lightnings in direct contact with water level was constructed.
The electrical discharges are powerful enough to cause dissociation
of water molecules in various ways. To facilitate the
electrical breakdown, the atmosphere in the reactor was replaced
by argon.
The water molecule can be broken by impact of sufficiently
fast electron, absorption of deep UV photon or previously excited
argon atom. Each of these processes has a different energy
balance and the remaining energy is partially conserved
. Typical example of a Boltzmann plot. The magenta curved line is a twotemperature
fit, where the blue and red straight lines are its components.
in quantum states of the water fragments. By careful analysis
of the light emitted by the relaxing OH radicals, we can disentangle
the respective contributions to the total spectrum and
calculate the portion of water molecules undergoing various
dissociation mechanisms.
The water fragments really remember what preceded their
creation and they let us know by emitting photons. The time
scale for "forgetting" depends on the collisional rate, i.e. the
pressure. At atmospheric pressure, the information can be kept
for several nanoseconds. n
llJ. Voráč, P. Synek, V. Procházka and T. Hoder,
'State-by-state emission spectra fitting for non-equilibrium
plasmas: OH spectra of surface barrier discharge at argon/
water interface', J. Phys. D: Appl. Phys. 50, 294002 (2017)
Astronauts to bring
asteroid back into lunar orbit
Italian Space Agency presents plans to develop a robotic
solar-powered spacecraft capable of displacing a near-
Earth asteroid towards lunar orbit for ease of study.
m How to bring an asteroid back nearer to lunar orbit.
Future space exploration aims to fly further from Earth than
ever before. Now, Italian Space Agency scientists have expressed
an interest in contributing to the development of
robotic technologies to bring an asteroid from beyond lunar
orbit back into closer reach in order to better study it. In
a paper published recently, the authors make the case for
taking part in the robotic phase of the Asteroid Redirect
Mission (ARM). In addition to taking manned spaceflights
deeper into space than ever before, the proposed mission
would also bring some benefit for planetary science. Further,
the mission has potential implications for a field called planetary
defence. The next step for human space exploration
after the International Space Station is to send astronauts
from european journals
on a Near Earth Asteroid by 2025, as planned by NASA. This
constitutes an intermediate step towards future manned
missions to Mars. The planned ARM mission has been part of
the NASA program since 2013.The robotic spacecraft would
cruise in deep space towards a near-Earth asteroid, using a
technology called advanced Solar Electric Propulsion. Under
the proposed plan, Italy would contribute by enhancing the
carrying capacity of that spacecraft. n
llM. Tantardini and E. Flamini,
'Synergies between human space exploration and
science in the asteroid redirect mission and the potential
Italian participation in the asteroid redirect robotic
mission phase', Eur. Phys. J. Plus 132, 314 (2017)
Monodisperse magnetic
nanoparticles prepared from
block copolymer template
material (magnetite) and exhibit very narrow size dispersion
(≈7%). They can be good contrast agents for medical
imaging. n
llM. Morcrette, G. Ortiz, S. Tallegas, H. Joisten, R. Tiron,
T. Baron, Y. Hou, S. Lequien, A. Bsiesy and B. Dieny,
'Fabrication of monodisperse magnetic nanoparticles
released in solution using a block copolymer template',
J. Phys. D: Appl. Phys. 50, 295001 (2017)
First aid kit in some living
organisms helps fix DNA
after lengthy sun exposure
New study unveils the binding mechanisms of enzymes
capable of repairing DNA damaged by UV light before
any risk of cellular malfunction sets in.
Magnetic nanoparticles are playing an increasing role in biomedical
applications, both for diagnosis, e.g. contrast agent
in MRI (Magnetic resonance imaging) or for MPI (magnetic
particles imaging) and for therapy thanks to their ability to
exert forces and torques on biological species allowing for
instance cancer cells destruction or oriented growth of biological
m Important photolyase residues for DNA binding.
m SEM images of superparamagnetic nanoparticles made from self-assembled
block copolymer template (a) on Si substrate, (b) after their release in solution.
In order to fabricate magnetic nanoparticles with high monodispersity,
required in particular in biomedical imaging, we
have developed a new preparation method based on the use
of self-assembled block copolymer template.
Such techniques have already been explored for the preparation
of patterned media for ultra-high density magnetic
recording. However, our requirements substantially differ
from those for storage media. A sacrificial layer has to be
introduced between the substrate and the diblock copolymer
to allow the release of the nanoparticles in solution.
For that purpose, an optimized germanium oxide layer was
used. The obtained superparamagnetic particles do not agglomerate
in solution. They can be made of biocompatible
Sunburn in living organisms is caused by ultraviolet (UV)
light from the sun damaging the DNA in the cells. Many
organisms, however, have an in-built mechanism for repairing
the sun damage. This is possible thanks to an enzyme
called DNA photolyase, which is so specialised that
cryptochrome, a structurally similar molecule, is unable
to do the same job. By comparing both types of molecule,
physicists can understand precisely how the ability of our
enzymes to repair DNA boils down to the most minute
structural details. In a study published recently, the authors
pinpoint the mechanism by which repair enzymes
bind to the damaged site. n
llK. Aalbæk Jepsen and I. A. Solov'yov,
'On binding specificity of (6-4) photolyase to a T(6-4)T
DNA photoproduct', Eur. Phys. J. D 71, 155 (2017)
llMairi Sakellariadou – DOI: https://doi.org/10.1051/epn/2017501
We live the golden age of cosmology, while the era of gravitational astronomy has
finally begun. Still, fundamental puzzles remain. Standard cosmology is formulated
within the framework of Einstein's General theory of Relativity. Notwithstanding,
General Relativity is not adequate to explain the earliest stages of cosmic existence,
and cannot provide an explanation for the Big Bang itself. Modern early universe
cosmology is in need of a rigorous underpinning in Quantum Gravity.
General Relativity, the well-known Albert Einstein's
theory, describes warps in space-time, and accounts
for the large-scale dynamics of the cosmos — the
dynamics of galaxies and clusters of galaxies, the
dynamics of black holes and even the dynamics of our Universe
— with an extraordinary accuracy. General Relativity
describes the way massive objects curve space-time, turning a
flat landscape into curved scenery of hills and basins. NASA's
Gravity Probe B mission [1], launched in April 2004, confirmed
two fundamental predictions of the theory of General Relativity.
With the help of very precise gyroscopes, Gravity Probe B
measured the warping of space-time around the Earth, as well
as the amount of space-time the Earth pulls with it as it rotates.
These effects are predicted by the theory of General Relativity
to be equal to 6606 milliarcsec/year and 39.2 milliarcsec/
year, respectively, while Gravity Probe B measurements lead
to 6602±18 milliarcsec/year and 37.2±7.2 milliarcsec/year, respectively
[2]. The accuracy is indeed remarkable.
In 1998, astronomical observations revealed that the Universe
undergoes an accelerated expansion, while naively one would
expect the expansion to be slowing down. Within the framework
of General Relativity, the late acceleration originates from dark
energy, with the simplest option being the cosmological constant,
first introduced by Einstein. However, in order to explain the
current acceleration of the Universe, the required value of the
cosmological constant must be incredibly small. Alternatively,
one may consider a large-distance modification to Einstein's
theory of General Relativity and relax the hypothesis of dark
energy. The explanation of the late-era accelerated expansion and
the unknown nature of dark energy remain open questions that
challenge our understanding of the Universe and question the
validity or completeness of our theoretical models.
Gravitational Physics
Relativity is not just an abstract mathematical theory with no
applications in our daily life. Special and General Relativity play
an important role in the Global Positioning System (GPS) which
requires nanosecond accuracy. Combining Special and General
Relativity effects implies that the atomic clocks on board of
each of the GPS satellites tick faster than identical clocks on the
ground by about 38 microseconds per day. If these effects were
not taken into account then errors in global positions would
accumulate at a rate of about 10 kilometers per day, rendering
the system worthless for navigation purposes.
The theory of General Relativity predicts the existence of
ripples in the fabric of space-time – called gravitational-waves
– produced during a violent event of an astrophysical or cosmological
origin in the faraway Universe. The existence of gravitational-waves
was first demonstrated by Taylor and Weisberg who
shown that the orbit of the Hulse-Taylor Pulsar (PSR 1913+16)
shrinks slowly over time – only 40 seconds over 30 years – as
the result of energy release in the form of gravitational-waves
[3]. In 1993, the Nobel Prize in Physics was awarded jointly to
Russell A. Hulse and Joseph H. Taylor Jr. "for the discovery of a
new type of pulsar, a discovery that has opened up new possibilities
for the study of gravitation". The hunt for gravitational-waves
lasted several years and the announcement of the first detection
in 2016 came 100 years after Einstein's prediction of their
existence [4].
According to the theory of General Relativity, a compact binary
system loses energy through gravitational-waves emission,
bringing the pair of compact objects closer to each other, until
a merger takes place leading to the formation of a single more
massive spinning compact object and the release of energy in the
form of burst of gravitational-waves. On September 14, 2015, the
two detectors of the Laser Interferometer Gravitational-Wave
Observatory (LIGO) [5] – located in Livingston, Louisiana,
and Hanford, Washington, USA – simultaneously detected a
transient gravitational-wave signal, hence confirming a major
prediction of Einstein's 1915 theory of General Relativity. These
gravitational-waves were produced during the final fraction of
a second of the merger of two black holes of roughly 29 and
36 solar masses – more massive than known stellar-mass black
holes – which took place 1.3 billion years ago, resulting in the
formation of a single black hole of 62 solar masses and the
release of an energy of 3 solar masses times the speed-of-light
squared, in the form of gravitational-waves [6].
The era of gravitational astronomy has then begun. Underpinning
this breakthrough is a technological triumph of
breathtaking capability. LIGO was able to detect movements in
objects equivalent to the width of a human hair at the distance
to the nearest star. The disturbances are tiny and their detection
requires an exquisite sensitivity. The LIGO interferometers
found a way to make measurements that go beyond the limits
imposed by the Heisenberg principle of quantum physics. On
the 3 rd October 2017, the Royal Swedish Academy of Sciences
has decided to award the Nobel Prize in Physics 2017 with one
half to Rainer Weiss and the other half jointly to Barry C. Barish
and Kip S. Thorne – all three members of the LIGO/VIRGO
Collaboration – "for decisive contributions to the LIGO detector
and the observation of gravitational waves". In announcing the
award, the Royal Swedish Academy called it "a discovery that
shook the world."
Gravitational-waves carry information – otherwise inaccessible
to us – from a variety of sources (e.g., phase transitions
in the early Universe, topological defects as relics of a previous
more symmetric stage of the Universe, an early inflationary era
which is a paradigm proposed to cure some of the pathologies
that plague the standard hot Big Bang cosmological model, or
mergers of compact binary systems formed by neutron stars
or black holes), opening a new window on our cosmic origins,
hence widening our understanding of astrophysics, cosmology,
as well as fundamental physics. Gravitational-waves can
be considered as the most promising cosmic relic to probe the
unknown aspects of the early Universe, as they can provide
information during the period that the Universe was opaque
to electromagnetic radiation.
Gravitational physics is now entering a golden age of discovery.
The Advanced Virgo detector [7] – located in Cascina,
Italy – joined the Advanced LIGO twin interferometers on August
1, 2017. Other detectors are planned to join the network:
KAGRA is being built in Japan [8], and LIGO India has been
recently approved. The Microscope satellite [9], aimed to test
the equivalence between gravitational and inertial mass, has
been successfully launched and is now taking data. Following
the highly successful LISA Pathfinder mission, the European
Space Agency has selected the space-based laser interferometer,
LISA [10], for its third large class mission, due for launch
in 2034. LISA will open a gravitational window on the Universe
in the low-frequency regime, providing the closest view
of the early stages of the Universe, from its smallest scales near
the horizons of black holes, all the way to cosmological scales.
There are also plans for the third-generation gravitational-wave,
such as the Einstein Telescope [11] or the Cosmic Explorer,
reaching unprecedented sensitivities, overcoming current limitations
imposed by thermal noise and quantum-optical noise.
These detectors will be roughly a factor of 10 more sensitive
in strain than the current generation, and be able to detect
binary black hole mergers beyond a red-shift of 20.
Despite its enormous success, the theory of General Relativity
has its limitations. The theory describes very well the dynamics
of the Universe through Einstein's field equations. Running these
dynamic equations backwards in time, there is a finite time in
the past when the Universe must have been in a state of ultrahigh
curvature and mass density. This is the Big Bang era, which
took place about 13.8 billion years ago and is considered as the
beginning of our observable Universe. At that early time, all
matter and energy of our present Universe were confined into
a tiny sub-atomic region of space, and the classical theory of
General Relativity cannot provide the mathematical tools and
physical concepts that will allow us to describe the behaviour of
gravity under such extreme curvature and density conditions.
Indeed, once we zoom into the microcosm, the behaviour and
position of sub-atomic particles become uncertain as we enter
the realm of Quantum Mechanics, characterised by uncertainties
and probabilities. To describe the Big Bang era, a quantum
theory of gravity is required; such a theory is expected to cure
the singularity which plagues the classical theory.
To address questions, such as what is meant by the origin
of the Universe, what was the mechanism that led to its creation,
whether its birth was an accidental process and whether
it could have been avoided, or even what was before the Big
Bang phase, requires an understanding about the state, structure
and dynamics of space-time itself. Quantum Gravity is the
theory aiming at explaining the shape of space-time and understanding
its invisible structure, which we perceive as the force
of gravity and which determines our own trajectories. Hence,
modern early Universe cosmology is in the need of a rigorous
underpinning in Quantum Gravity, the long-sought theory that
will offer the appropriate framework to address fundamental
questions such as the origin of the space-time continuum and
its effective dynamics, and the pictures of the earliest moments
of the Universe which emerge.
Different Quantum Gravity proposals have been made and
progress has been constantly achieved. These proposals belong
to two classes; they are either top-down (guess the structure of
space-time at the Planck scale and deduce its consequences at
low-energy scales) or bottom-up (deduce the structure of spacetime
at the Planck scale from our knowledge at low-energy
scales at which colliders operate). In the former class belong
approaches like String/M-theory or a variant of non-perturbative
approach to Quantum Gravity, like Loop Quantum Gravity
[12], Group Field Theory [13], Causal Sets [14], or Causal
Dynamical Triangulations [15]. In the latter one belong the
proposal of Non-Commutative Spectral Geometry [16] and
that of Asymptotic Safety [17]. At present, Quantum Gravity
has spawned many new ideas aimed at augmenting or replacing
General Relativity as a theory of gravity. The low-energy limit
of such Quantum Gravity theory will be the classical theory of
General Relativity.
Applied to cosmology, these ideas involve dramatic departures
from the standard cosmological model [18], such as bouncing
cosmological models, where the Universe undergoes a long,
pre-big bang contracting phase which then bounces into the
expanding Universe we observe today. Another possibility is an
early era of accelerated expansion without the need for a special
mechanism such as inflation. These ambitious attempts to model
the very early Universe mathematically have been accompanied
by plans for observational tests. Searching for physical remnants
of very early Universe, not to mention a possible pre-big bang
phase, are enormously challenging, but gravitational-waves are
acknowledged as the most promising. At present, even though
we are not yet in a position to make any definite statement as
to which – if any –Quantum Gravity proposal is viable, it is fair
to say that a great progress has been made towards the goal to
unify gravity with sub-atomic forces. Early Universe cosmology
can shed some light on the correct Quantum Gravity theory,
unweaving the fabric of the Universe and revealing the very
early stages of its infancy [19]. n
About the Author
Mairi Sakellariadou, Professor of Theoretical
Physics, King's College London. Research in Early
Universe Theoretical Cosmology, Quantum Gravity/Cosmology
(String/Brane Cosmology, Loop
Quantum Cosmology, Group Field Cosmology,
Non-Commutative Geometry), Gravitational-Waves,
Modified Gravity, Topological Defects.
LIGO Scientific Collaboration, GEO600 Experimen, MoEDAL
at LHC Collaboration, LISA Cosmology working group, Einstein
Space Team, EUCLID Consortium, Virgo Ego Scientific Forum
Chair of the Gravitational Physics Division of the European
Physical Society
President of the Hellenic Society Relativity, Gravitation
and Cosmology
Advisory Editor for Springer Verlag books
Co−editor of Europhysics Letters
Member of the Editorial Advisory Board of Classical and Quantum
Emily Noether Visiting Fellow at the Perimeter Institute, Canada
Member of the Advisory Committee of the Research and Training
Group "Models of Gravity", Germany
[1] https://www.nasa.gov/mission_pages/gpb/
[2] C. W. F. Everitt, D. B. DeBra, B. W. Parkinson, J. P. Turneaure, J. W. Conklin,
M. I. Heifetz, G. M. Keiser and A. S. Silbergleit et al., Physical Review Letters
106 (2011) 221101
[3] J. H. Taylor and J. M. Weisberg, Astrophysical Journal 253 (1982) 253
[4] A. Einstein, Sitzungsber. Preuss. Akad. Wiss. Berlin (Math.Phys.) (1916) 688
[5] http://www.ligo.org/
[6] B. P. Abbott et al. (LIGO Scientific Collaboration and Virgo Collaboration),
Physical Review Letters 116 (2016) 061102.
[7] http://www.virgo-gw.eu/
[8] http://gwcenter.icrr.u-tokyo.ac.jp/en/
[9] https://microscope.cnes.fr/en/MICROSCOPE/index.htm
[10] http://sci.esa.int/lisa/
[11] http://www.et-gw.eu/
[12] A. Ashtekar, New J.Phys. 7 (2005) 198
[13] D. Oriti, in Mathematical and Physical Aspects of Quantum Gravity,
B. Fauser, J. Tolksdorf and E. Zeidler, eds., Birkhaeuser, Basel (2006).
[14] L. Bombelli, J. Lee, D. Meyer, and Rafael D. Sorkin, Physical Review
Letters 59 (1987) 521.
[15] J. Jurkiewicz, R. Loll and J. Ambjorn, Scientific American (July 2008)
[16] A. Connes, J. Mathematical Physics 41 (2000) 3832
[17] R. Percacci, in Approaches to Quantum Gravity: Towards a New
Understanding of Space, Time and Matter, D. Oriti, ed. Cambridge
University Press (2008)
[18] M. Sakellariadou, Journal of Physics: Conf. Series 880 (2017) 012003
[19] M. Sakellariadou, in Mathematical Structures of the Universe, edited by
the Copernicus Center for Interdisciplinary Studies (2014).
llAntigone Marino – DOI: https://doi.org/10.1051/epn/2017502
llInstitute of Applied Sciences and Intelligent Systems, National Research Council
c/o Physics Department, University of Naples Federico II, Italy
Lying on the remote north west coast of England, Sellafield is one of the most secret
places in UK, and even one of the most controversial nuclear fuel reprocessing and
nuclear decommissioning sites in Britain. The film director Tim Usborne let us enter
into the world's first nuclear power station, revealing Britain's attempts to harness the
almost limitless power of the atom. It is precisely the simplicity and the scientific rigor
used in the film to speak of nuclear, which led this documentary to win the Physics
Prize supported by the European Physical Society at the European Science TV and
New Media Festival and Awards 2016.
Inside Sellafield
b P. 21: Jim
Al-Khalili is a British
Iraqi theoretical
physicist, author and
broadcaster. He is
currently Professor
of Theoretical Physics
and Chair in the
Public Engagement
in Science at the
University of Surrey.
He has presented a
number of science
programmes on
BBC television
and is a frequent
commentator about
science in other
British media.
You will be wondering if EuroPhysics News is
really about to reveal the secrets of English
nuclear. And that's what thousands of spectators
have asked for in front of the award-winning
documentary film "Britain's Nuclear Secrets: Inside
Sellafield" by Tim Usborne. Winner of the Physics Prize
at the European Science TV and New Media Festival and
Awards 2016, the documentary brings you into one of
the biggest nuclear power plants in the world, Sellafield.
Lying on the remote north west coast of England, Sellafield
is one of the most secret places in UK, and even
one of the most controversial nuclear fuel reprocessing
and nuclear decommissioning sites in Britain. Moreover,
it is the site of the world's first commercial nuclear power
station to generate electricity on an industrial scale. In just
one hour the nuclear physicist Professor Jim Al-Khalili
presents to the general public the physics that allows UK
to produce energy. The narrative rhythm is intense, the
spectator discovers step by step the most dangerous substances
on earth, the nature of radiation and how to split
the atom. The crescendo has its maximum when cameras
enter into one of the nuclear reactors. The documentary
faces one of the hottest physics issues for civil society, the
nuclear production of energy, revealing Britain's attempts
- past, present and future - to harness the almost limitless
power of the atom.
It is precisely the simplicity and the scientific rigour
used in the film to speak of nuclear, which led Tim Usborne
to win the Physics Prize supported by the European
Physical Society. The European Science TV and New
Media Festival started in 2001, as a way of recognizing
and promoting the value of science in non-science TV
productions, and notably TV drama which reach large
audiences. Following early success, the festival expanded
its agenda and now encompasses science and technology
in all genres of television and new media. Since 2015
the festival assigns a special prize to productions having
physics as science subject. Andrew Millington, Festival
and Awards Director, explains us that three criteria are
used to judge entries. Firstly, the quality of the physics
being presented. In other words, the physics message.
Secondly, the production values of the films, such as the
quality of the filming, pacing of the narrative and the
script. And thirdly, whether it was innovative in some
way, either through selection of the content or the method
of presentation.
Behind a documentary like this, one wonders how
much work there is. Not just for direction issues, but also
for the scientific tasks needed to give scientific validation
to the story. That is why we interviewed the film director,
with some questions aimed at understanding what are the
steps for the realization of such a bold project.
Tim Usborne is a UK based documentary film maker,
mainly specialising in science. He has made films about
the Nuclear Industry, Chemical Weapons, a history of
Trains, Quantum Physics, Alien Life, the History of Electricity,
and a 3D series about the lives of insects. His films
have been broadcast by the BBC, Channel 4, Discovery,
National Geographic Channel and many other UK and
international broadcasters. He is currently producing
BBC landmark series, The Sky At Night, about astronomy
which has been on air for over 60 years.
c FIG. 2: On the 18 th
November 1983,
something happened
here that damaged
Sellafield's reputation
irrevocably. That
morning scientists
at Sellafield looked
out to sea and saw an
inky black slick. It was
a slick pouring out
of Sellafield. People
started questioning
whether the whole
plant should be closed
down altogether .
In the picture, the
troupe filming the
beach where the
accident took place.
Inside Sellafield
b FIG. 3: The film
Director, Tim
Usborne, is a UK
based documentary
film maker, mainly
in science.
Antigone: Nowadays, scientists are asked to be good
communicators. Social media and the intensive use of
videos to present scientific results require specific skills.
What is needed to produce a good scientific documentary
is the ability to translate the scientific language into
everyday life talk. How did you manage to do it? Have you
had any specific studies or courses? If a young scientist
decides to take this road (of documentary director) what
advice would you give him/her?
Tim: I have been working in television for nearly thirty
years. When I started out, I didn't have a specific idea
of making science documentaries, despite having a science
degree. In fact, over that time I made all sorts of
television programmes - live events, sports, children's,
entertainment, drama.
But then over the last ten years, I found myself making
more and more documentaries and when the chance
came up to make a film about science I jumped at it. And
I've been working in science documentaries ever since.
I would recommend that someone starting out in TV
who wants to make science films should probably first get
work as a research runner at a TV production company.
The BBC has work experience opportunities for instance.
There are a few courses I might recommend too, for instance
Imperial College London runs a master's degree in
science communication which is well thought of. But don't
feel that you have to start in science TV - you can learn
the craft of television first, and then focus on science later.
Antigone: Your documentary deals with a very delicate
and sensitive subject for society. I suppose you have a
personal opinion on nuclear power. Did making this
documentary change your mind? Or has it somehow
strengthened your previous idea?
Tim: I started making this film ambivalent towards nuclear,
probably slightly pro, as long as it was well managed
and legislated. During the filming, I saw some of the
pitfalls of the industry, and have become aware that the
industry is often less than perfect, so it made me think
that if we are to have this industry - and there is much
debate about whether that should happen or not - then
the only way to manage it is extremely carefully, and with
a long term view.
Antigone: I can imagine that the hardest part in making
this documentary has been the bureaucracy that you and
the staff had to overcome in order to enter the nuclear
power plant and make the recording. Have these rules
limited your creativity and the message of the documentary?
Does this often happen?
Tim: It took over two years for us to get the paperwork
signed to get access to Sellafield to make the film. It first
had to be agreed with the nuclear industry, and the British
Home Office and British government. But once this was
in place, Sellafield agreed that they would have no say over
the editorial of the film - so we could tell the story we felt
was important. But, having said that, we knew from the
start that the story we were telling was not about the pros
and cons of the nuclear industry, it was always about the
science and history of the industry,
Antigone: Inside Sellafield has two strength points: it
speaks of a hot topic people like to hear, and brings the
viewer into a secret place. In your opinion, what is the
one that has most fascinated the public?
Tim: I think what made this film so successful was that it
gave us a chance to see inside a place which has remained
secret for so long. And that was made more significant
given that what happened there was so important for
all of us.
Antigone: This year, the March for Science was celebrated
all over the world, a global event to make governments
aware of the importance of science for societies. Do
you believe that scientific documentaries also have this
function? And do you believe a greater interaction of the
science world with that of large-scale disclosure could
facilitate the transmission of this message?
Tim: Science documentaries are a chance to show the best
(and sometimes the worst) of the world of science to the
general public. It is our duty as science communicators
to make sure we do this as effectively as possible.
And as science becomes more and more specialised
- and at the same time more and more at the heart of
our society – it is critical that these kinds of messages
get out. Science needs to communicate or it will become
estranged from society.
Antigone: Did you imagine that the documentary would
win the Physics Prize by the European Physical Society?
In a world where the quality of a product is measured
by the number of likes or visualizations, do you think
an achievement like this is unflagging or can also have a
value for the documentary distribution?
Tim: Certainly winning was a great surprise – it's a great
honour to win, and I know all the team involved feel very
pleased to have won such a prestigious award. I hope that
the prize might bring about interest in the film and the
subject to new audiences.
After this interview I watched the documentary for
the third time. Once again I am amazed by the clearness
of the scientific message. When Jim Al-Khalili has to explain
how to trigger the chain reaction he shows a box
with 120 loaded mousetraps, each with a ping pong ball
on it. Dropping a single ball in on top of the box, one
ball triggers more and more in the mousetrap, starting
the chain reaction. That's how it works in a reactor. As
each uranium atom splits, it also releases neutrons. And
just like the ping-pong balls triggering the mousetraps,
these neutrons could split new uranium atoms. The Uranium
would trigger a massive nuclear chain reaction.
Plus producing enough neutrons to turn some of the
Uranium into Plutonium. Historically all this science
was focused on the realization of nuclear bombs. But
for nuclear physicists there's another way to use all this
scientific knowledge. The same nuclear science that had
split the atom to make a bomb has the potential to produce
almost limitless cheap energy. Because in addition
to producing Plutonium the reactor produced heat, and
that heat could be harnessed. As Jim says, "The dream was
that the power of the atom would come out of the shadow
of the bomb, and into our living rooms…As electricity!".
That is what happened in 1952 in Sellafield: work began
on an ambitious experiment in power generation that
would shape the modern world. It was called Calder Hall,
opened in 1956. During the celebration the Queen said:
"This new power which has proved itself to be a terrifying
weapon of destruction is harnessed for the first time for
the common good of our community". On 27 th August
1956 heat generated from the nuclear chain reaction was
used to turn water into steam that turned a turbine and
made electricity. And that electricity was poured for into
the National Grid, making Sellafield the world's first Nuclear
Power station.
Unfortunately, the knowledge of physical processes
such as those explained in this article can be used for
war purposes. In times with a high tension between
nuclear-armed states a clear message was given by the
Norwegian Nobel Committee, which awarded Nobel
Peace Prize to the International Campaign to Abolish
Nuclear Weapons (ICAN) "for its work to draw attention
to the catastrophic humanitarian consequences of any use
of nuclear weapons and for its ground-breaking efforts to
achieve a treaty-based prohibition of such weapons".
Thirty years ago my country (Italy) chose with a referendum
to abolish nuclear facilities. It was 1987, just
one year after the Chernobyl accident. I was a child. I
did not know I would study physics. I just remember
that the YES won, and everyone was celebrating the result.
I wonder how many Italians knew at that time the
difference between alpha, beta and gamma particles. I do
not think this number has changed so far. That's why a
documentary like this one I'm talking about has a very
strong social value. Because it explains nuclear, without
demonizing or taking part. The spectator will then make
his choice, pro or contra. But after the documentary his/
her opinion will be supported by scientific information.
That is why we don't just have to do science, but also
explain it. n
About the Author
Antigone Marino is researcher at the
Institute of Applied Sciences and Intelligent
Systems of the Italian National
Research Council in Naples, Italy. Her
research activities are concentrated on
the study of soft matter optic. Since 2016
she is jury member of the European Science TV and New
Media Festival and Awards.
llJean-Sébastien Caux – Institute of Physics, University of Amsterdam – DOI: https://doi.org/10.1051/epn/2017503
Scientific publishing is currently undergoing a progressively rapid transformation away from
the traditional subscription model. With the Open Access movement in full swing, existing
business practices and future plans are coming under increasing scrutiny, while new
"big deals" are being made at breakneck speed. Scientists can rightfully ask themselves
if all these changes are going the right way, and if not, what can be done about it.
Fortunately, in this day and age, some spheres
of human activity remain anchored in rational
thinking, evidence-based debate and
error-corrected progress. Scientific research
undoubtedly fits in this category: few scientists doubt
that reason should prevail over nonsense. Yet, when it
comes to publishing, the scientific world seems to be
bathed in a maelstrom of irrational hogwash. What is
going on? What can we do about it?
A business unlike any other
Scientific publishing, as a business, has become a truly
unique inverted pyramid construction in which the
"customers" pay dearly for accessing the product after
actually performing themselves all the irreplaceable,
not-doable-by-others steps in the manufacturing process.
Historically, this tour-de-force of business abracadabra
has been achieved in no small part by exploiting
the other dubiously-implemented aspect of publishing,
m © iStockPhoto
scientific publishing
namely impact assessment. The often-heard complaint
that where you publish matters more than what you
publish underlines the undue influence publishers now
have on the lives of scientists (especially younger ones).
What could be called the "impact of the impact factor"
has greatly curtailed the liberty that scientists should
enjoy to author their papers and evaluate their importance
in a rational and collected manner. Publishing
has thus become a kind of three-headed hydra which
generates profit out of scientists' daily achievements
and holds their career development prospects hostage,
whilst discouraging them from presenting the
fruits of their work in a cool, detached, scientifically
professional manner.
Open Access and drifting business models
It is no wonder, then, that we have recently witnessed a
great many discussions concerning reform of the whole
scientific publishing edifice. Though much needs to
be done, the Open Access "movement" has been at
the forefront of discussions, as exemplified by a string
of statements (including Budapest [1], Bethesda [2],
Berlin [3] and most recently Amsterdam [4]) underlining
involvement and desire for reform from
interested parties at all levels. Strangely enough, the
growing cacophony of voices has blurred even the
very definition of "Open Access". In its simplest and
most common form [5], OA simply signifies that
10-karat (openness to readers: open access):
- make full text of publications freely available to readers
(Creative Commons license)
14-karat (openness to authors: copyright, embargo):
- copyright is given to the authors without restrictions
- publishing occurs without any embargo period
18-karat (openness to users: reuse, remix, crawl, citations):
- publication license allows reuse and remixing of content
(Creative Commons Attribution (BY), Share-alike (SA)
or Non-commercial (NC) licenses)
- publisher allows text mining (software/spiders can
automatically crawl journal content)
- publisher makes its citation data publicly available (ideally
via participation in I4OC)
22-karat (openness to reviewers: open reports):
- refereeing reports are openly visible and citable
24-karat (openness to community: academic ownership):
- the responsibility for publication decisions is entirely in the
hands of active professional scientists.
readers can access published material without having
to pay subscription or per-view charges; but to some,
it means much more. That said, much of the attention
recently devoted to OA has in fact been diverted
towards financial matters, with vitriol often being
poured on the undeservedly high profit margins that
a number of corporate publishers have historically
managed to get away with. A new payment model
has been developed and mandated, deprecating the
journal subscription model and replacing it by an
"author pays" model in which publishers require authors
(or, in practice, their funders, institutions or
societies) to pay an Article Processing Charge (APC)
typically ranging from a thousand euros up to a large
multiple of this figure to make the contents openly
accessible upon publication ("Gold" OA). To facilitate
rapid implementation of OA, a softer version,
"Green", has also been introduced. In this version,
authors deposit (after respecting eventual embargo
impositions from the publisher) a version of their paper
in an openly-accessible repository (institutional,
or community-run like arXiv). Although solving the
accessibility problem, Green OA implementations fall
short of representing a full substitute and deprecator
for the services publishers offer, leaving the desire for
publisher reform adrift and unfulfilled.
Sportscars, jewels, rare stamps
and failed markets
One of the often-mentioned rationales behind the introduction
of APCs is that "opening up the market" would
help drive publication costs down. However, there is a
simple yet fundamental problem here, namely: scientific
publishing is an industry in which prestige and reputation
are at stake. Publications are not dissimilar to sportscars,
jewels or rare stamps: their market price has nothing to do
with their production costs. As a researcher, if I estimate
that publishing in a specific journal gives me, say, 5%
more probability of getting a million-level grant, then
being asked to pay 1500 euro APCs seems like a bargain,
since I would still evaluate it as worthwhile to pay an order
of magnitude more. Of course authors cannot "buy" their
way into premium journals, so this pseudo-economic
calculation actually makes no sense whatsoever. As a
scientist, I don't actually care what the APC is (I'll pass
the bill to my funders or institutional library); I only care
about the quality and reputation of the publication venue.
The problem is thus that the APC model has opened a
Pandora's box of potentially diverging publication costs
at the high end of the market, with no mechanism to
bring them down. This damaging dissociation of quality
with price level has in fact had the counterproductive
effect of driving some publishers to increase their
APCs in order not to be viewed as lower-quality [see
e.g. the Finch report [6], while fueling the proliferation
scientific publishing
of so-called "predatory open access" journals in which
editorial processes are curtailed in order to quickly cash
in on artificially-inflated APCs. When markets work, they
work. When they don't, they can turn a whole industry
into a disastrous and nonsensical comedy.
Big Deals and cost consciousness
Another oft-forgotten point is that markets can only work
when openness reigns. One of the most criticized aspects
of the old and current systems is that the actual costs
of subscriptions were often negotiated and kept hidden
behind closed doors due to the imposition of non-disclosure
agreements on institutions by publishers. Scientists
in particular were (and still are) more or less totally unaware
of the sums paid by their institutions to give them
access to literature. The introduction of APCs thus had
some positive impact by suddenly making researchers
more cost-aware, albeit in a very incomplete, incorrect
but still shock-inducing manner.
On the broader economic side, much has been discussed
about the non-scalability of APCs. Institutions,
even top ones, will not be able to afford the sums involved
in an eventual sudden transition to APCs if these
remain at current levels (let alone increase!). On the
other hand, the very transition from subscriptions to
APCs has led to the appearance of the "double dipping"
phenomenon, whereby journals that still charge subscription
fees nonetheless also charge APCs to subsets
of willing authors to make their particular publications
openly accessible, thereby putting even more financial
pressure on university libraries than in the subscription
era. "Big Deals" between institutions and publishers
are also often in the news these days, in which whole
swathes of academics suddenly learn that they can publish
"free of charge" in particular journals. Although
making researchers' administration work simpler, it also
makes them blind to the financial realities involved in
publishing. I have often reminded colleagues that this
or that journal, while perhaps "open access", is certainly
not "free of charge", and that through all their Big Deals,
many institutions are repeating history and condemning
themselves to face increasingly severe budgetary restrictions
through their lack of power in forcing reform of
publishers' practices (and thus of their finances).
A better model
In a very encouraging development, alternatives to current
business practices are rapidly emerging. In physics,
we have for the best part of three decades benefitted from
the arXiv preprint server, which is funded according to
a consortial model in which many institutions provide
small-scale funds that (when added to some larger institutional
grants) allow the whole infrastructure to be
maintained and developed. This consortial funding
model is now starting to be applied with success to the
Gold [Au]:
- APC-based financing
Platinum [Pt]:
- publisher does not apply any charges to authors (APCs,
submission charges or any other), and is funded through a
consortial model or equivalent
Palladium [Pd]:
- publisher runs a purely not-for-profit public enterprise: none
of its activities generate any profit, and all financial statements
are publicly disclosed.
Combinations: In this scheme, Au and Pt are incompatible;
Pt naturally binds with Pd, while Au and Pd can also
mix consistently.
business of publishing, the best-known example being
the Open Library of Humanities [7], which gathers institutional
contributions to cover publishing costs (no
APCs being charged). Looking at the figures [8] makes
it patently clear that overall, this model is much more
economical than either subscription or APC-based ones,
and is the most credible way of applying downwards price
pressure in the publishing market. The real question is
why this has not been implemented more broadly.
Noble metals for a noble cause
Let us briefly change tack and perform a small but worthwhile
exercise, which consists of resolving the developing
confusion of what Open Access actually signifies, precisely
what "Gold" entails, and whether one can actually try
to differentiate between its different sorts.
First, the obvious: to call itself a publisher, an entity
should perform at least basic tasks, such as runnig a strict
quality-controlled peer review process, ensuring ISSNs
for its journals, running professional-level post-acceptance
production, operating an online platform for its
content, providing metadata handling (registration of
DOIs), providing linking of funding information back
to funders and ensuring perpetual availability via a dedicated,
digital archiving and preservation service. None
of this qualifies as rocket science.
Turning now to Open Access, expectations scale up.
Since gold (as a commodity) comes in different levels
of purity, let us be inspired by metallurgy and adopt
karat-level resolution for Gold content 1 , in order to
A more technically correct and modern scheme would be to use fineness (parts per
1000), but this leaves out all the desirable poetry.
scientific publishing
differentiate the levels of open accessibility being delivered.
One could propose the requirements in Box 1.
One could perhaps debate the precise contents and ordering
of this list, which in any case does not include
all requirements one might think of. Still, it's a good
start; but is it possible to go even further? What about
more details on the business model? One commonly
used label is to call non-APC publishers "Platinum"
instead of Gold. Box 2 extends this even further by introducing
"Palladium" to denote consortial-financed,
not-for-profit publishers. Possible material combinations
are also given.
Though karats are not traditionally used for precious
metals other than gold, let us bend the rules and characterize
publishers according to their business model
(Gold (Au), Platinum (Pt) and/or Palladium (Pd)) together
with their openness karat rating. One can then
identify some publishers as Gold 18-karat, Platinum
22-karat, etc, allowing for a simple "lifting of the degeneracy"
in the current nomenclature which packs too
many things under the simplistic "Gold" label. Abbreviation
fans can thus argue about whether they find Au10k
publishers acceptable (some would call this category
"Fool's Gold"), or whether they insist that Pt/Pd24k is
the crème de la crème and the only model worthy of
their support. Funders and institutions that are sufficiently
forward-thinking about meaningful mandates
could decide to reimburse APCs (up to a cap) only for
18-karat and above publishers, with a lower cap for non-
Pd ones. On the workfloor, scientists could decide to not
do any unpaid refereeing or editing work for non-Pt/
Pd publishers.
For talking about Open Access
to doing it: SciPost
About two years ago, after much thinking on these
issues, I decided to heed my colleagues' retort "if you
care so much about it, why aren't you doing anything?"
and founded SciPost, a nonprofit foundation whose
online portal SciPost.org (launched in 2016) offers a
complete framework for publishing (according to the
classification proposed here, SciPost is a fully-featured
Platinum/Palladium 24-karat publisher). For many
people, this has rapidly become a demonstration of
the fact that scientists are most often best served by
themselves. With a strong start to its publishing activities
in its first year, the first journal SciPost Physics is
rapidly gaining recognition as a force for innovation.
The results obtained until now amply justify the interminable
hours of pro-bono work that I and many
others have put into it, and pave the way towards a
better and healthier publishing system. With its operating
costs estimated at around 300 euros per publication
(about a factor of 5 lower than the current
norm), SciPost is in a position to be an alternative in
the publishing industry. Having managed to convince
scientists that our services constitute a proper alternative
to existing practices, our next challenge is to
convince funders, universities and libraries that it is
in their interest to support and join our cost-slashing
consortial funding model.
The driver for change
Although we are far from done (we haven't even begun
discussing impact assessment!), let us end here
by performing a simple thought experiment. From
next January, for a period of 3 years, imagine that
all scientists agreed to exclusively submit their manuscripts
to new emerging not-for-profit publishers
fulfilling Platinum/Palladium 18-karat and above
open access criteria (simultaneously, they would
exclusively perform refereeing and editorial work
for such publishers). What would happen then? By
simply voting with their feet, scientists could exert
overwhelming influence and drive the necessary
transition to open access through all currently existing
or perceived obstacles. Ultimately, the power
to enforce change resides in the hands of us scientists:
it is up to us to decide the future we want to see in
publishing, and to make it happen in the way we
want; namely, in the interests of what we love the
most and is only too often forgotten in Open Access
discussions: science itself. n
About the Author
Jean-Sébastien Caux is Professor of
Theoretical Physics at the University
of Amsterdam. His work focuses
on strongly-correlated systems in
magnetism, cold atoms and quantum
nanostructures. Born in Canada,
he pursued graduate studies in Oxford as a Rhodes
Scholar, thereafter working as Postdoctoral Fellow
in All Souls College, finally moving to Amsterdam
in 2003. He is the recipient of the NWO Vici and ERC
Advanced grants.
[1] http://www.budapestopenaccessinitiative.org/read
[2] http://legacy.earlham.edu/~peters/fos/bethesda.htm
[3] https://openaccess.mpg.de/Berlin-Declaration
[4] https://www.government.nl/documents/reports/2016/04/04/
[5] https://en.wikipedia.org/wiki/Open_access
[6] https://www.acu.ac.uk/research-information-network/finch-report
[7] https://www.openlibhums.org
[8] https://www.martineve.com/2016/06/16/consortial-purchasingand-downward-price-pressure-for-open-access/
[Physics in daily life]
by L.J.F. (Jo) Hermans
Leiden University, The Netherlands - firstname.lastname@example.com - https://doi.org/10.1051/epn/2017504
Fascinating friction
If surfaces are slippery, it is usually because they are
wet. This is the case even for ice: our skates glide
smoothly across the ice because they glide across
a thin layer of water. And so does a hockey puck.
Water makes slippery, this much we know. So it should not
come as a surprise that oil and grease also reduce friction.
After all, they form a thin layer of fluid between two solid
surfaces and thus provide lubrication.
Lubrication between dry surfaces can also arise if both
surfaces are covered with patches of a well-ordered smooth
layer of, e.g., graphene, but with the patches randomly
oriented. Think of two
washboards, which glide
smoothly across one another
at random orientations
except if the ridges
happen to be aligned.
But what about the
friction between two ordinary
dry surfaces? Let
us first remember that
the friction coefficient
– the ratio between the
friction force and the
normal force – is smaller
when the surfaces are
moving relative to one
another than when they
are static. This has an interesting consequence: the stick-slip
behaviour. We know this phenomenon, e.g., from a bow over
a violin string. The bow starts to move across the string if the
driving force exceeds the static friction. It then slides over the
string with the smaller dynamic friction until it reaches the
point where the driving force is reduced to the level of the
dynamic friction force. At this point the motion stops and
driving force builds up again, making the bow ready for the
next hop. The high frequency at which this entire process
occurs produces the singing of the violin.
What kind of values do friction coefficients have? Obviously,
they depend on the two surfaces involved. Approximate
values are typically between 0.04 for Teflon on steel
to 0.8 for the static friction of steel on steel.
Can the friction coefficient reach values larger than 1?
Why not? In fact, in some cases it does. And you know it
does. Everybody who has seen motorcycle racing on TV
has observed that, in curves, the bike can lean over by an
angle larger than 45° with respect to the surface normal.
A simple force diagram shows us that, indeed, the static
friction coefficient exceeds unity in this case, thanks to
the silicone rubber or acrylic-rubber-coated tire surface.
Another striking property of friction, which most
of us take for granted since our high-school physics, is
the fact that the friction only depends on the normal
force and the type of
surfaces, but is independent
of the surface
area. If considered
from a microscopic
point of view, this flies
in the face of common
sense. The solution to
this problem is that this
'area' is the apparent
surface area. True
atomic contact is established
only in a
small fraction of this
area, even for polished
surfaces. Elasticity of
the contacting surfaces
and/or their plastic response makes the true contact
area approximately linear in the normal force. Problem
It may be clear that much about friction is as yet poorly
understood. Our present understanding is still at a
semi-phenomenological level. Nobody has been able to predict
the friction coefficient for a given system. Fortunately,
the young and rapidly developing field of nanotribology
is on course to clear up much of the friction mysteries, as
is done for example by Joost Frenken and his group 1 in
Leiden/Amsterdam. And since friction is responsible for
a substantial fraction of the cost of mechanical equipment
in wear and energy use, this work may soon save some
money in our daily life… n
The physics of atomic-scale friction: basic considerations and open questions; S.Yu. Krylov and J.W.M. Frenken, Review paper
(invited), Phys. Status Solidi B 251, 711 (2014)
llMatilda Backholm, Jaakko V. I. Timonen*, and Robin H. A. Ras* – DOI: https://doi.org/10.1051/epn/2017505
llDepartment of Applied Physics – Aalto University – P.O. Box 15100, 02150 Espoo, Finland
l l* Email: email@example.com, email@example.com
Superhydrophobic surfaces let water droplets roll off with low friction and falling
droplets rebound, leaving the surfaces completely dry. Such extremely water repellent
surfaces are found in nature on lotus leaves, the legs of water striders and feather
coatings of birds, and portray a beautiful example of ingenious biological design. They
provide an exciting research avenue for physicists and materials scientists aspiring to
understand and mimic nature.
. Photo by
Mika Latikka
A physicist's approach
to superhydrophobicity
Superhydrophobicity, that is the extreme fear of water, is
a fascinating surface property found in nature on many
plants and insects. The strong water repellency is often
crucial for surviving in harsh conditions: the superhydrophobic
surface on submerged insects, for example,
traps small air pockets on their bodies that act as an
external lung to allow gas exchange and breathing underwater.
Barthlott and Neinhuis realized in 1997 that
the intriguing self-cleaning nature of a lotus leaf arises
from the combination of surface microroughness and
a low-surface-energy wax nanocrystal coating (Fig. 1a)
[1]. This discovery opened an exciting avenue for scientists
aspiring to mimic the designs found in nature
to manufacture artificial superhydrophobic substrates.
Slippery and never wet
The grand goal is to produce a world of self-cleaning,
non-wetting, anti-fouling, flow-enhancing, anti-icing,
and anti-fogging materials, just to name a few examples.
Currently, the major bottleneck towards commercialization
of superhydrophobic surfaces is the fragility of
the micro/nano-structured substrate. A damaged surface
region will make drops stick to the material and vastly
degrade the final product. Intense research is currently
being performed to create new, mechanically robust alternatives
Today, the most common physical model of a superhydrophobic
surface is made of an array of micron-sized
pillars coated with a hydrophobic film (Fig. 1b). When
a water droplet is placed on the surface, air becomes
trapped within the micropillared structure (Fig. 1c-d).
The droplet thus rests mostly on a cushion of air, visible
as a thin ray of light between the droplet and the solid
substrate. This is called the Cassie wetting state and allows
for very high contact angles (θ >150°) and extremely low
droplet friction and adhesion. Recently, beautiful sideview
projections utilizing confocal microscopy from the
Butt group provided a high-resolution view of the contact
line of a droplet in the Cassie state (Fig. 1e) [4]. Detailed
information on the microscopic motion of the contact
line was also gained, shedding light on the fundamentals
m FIG. 1: The physical model of a superhydrophobic surface. (a) Scanning electron microscopy (SEM)
image of the surface of a sacred lotus (Nelumbo nucifera) leaf (scale bar 20 μm). Picture adapted from [1].
(b) SEM image of an artificial micropillared surface (scale bar 20 μm). Image by Anas Al-Azawi.
(c-d) Photo and schematic illustration of a millimetric water droplet in the Cassie state on a micropillared
superhydrophobic surface. An air layer is trapped within the microstructure beneath the droplet,
rendering a very high contact angle θ. Photo by Mika Latikka. (e) Confocal microscopy image of the
three-phase contact line of the drop (pillar spacing 30 μm for scale). Picture from [4].
"The grand goal is to produce a world of self-cleaning,
non-wetting, anti-fouling, flow-enhancing,
anti-icing, and anti-fogging materials.
. FIG. 2: Transitions between wetting states. (a) Schematic illustrations of irreversible and reversible
wetting transitions on a single (left) and dual-level (right) topography, respectively. (b) The
compression (plate/substrate gap denoted by z, plate direction by arrow) of a droplet on a micropillared
superhydrophobic surface with single (left) and dual-level (right) topography. In the former, the droplet
irreversibly undergoes a transition to the Wenzel state, whereas the latter allows for a reversible
transition. The two first, central images (black boxes) show experiments on a dual-level surface, but
also capture the initial stages on the single-level surface. The Cassie state is noted by the bright region
between the drop and the surface. Pictures in (a) adapted from [6] and (b) adapted from [7].
Slippery and never wet
behind the almost unhindered dynamics of droplets on
these surfaces.
Reversible wetting transitions
The Cassie state is crucial for superhydrophobicity
to arise. Unfortunately, pressure fluctuations, such as
from an impacting droplet, can collapse the air cushion
between the water droplet and the solid substrate,
resulting in water to wet the surface completely, called
Wenzel state (Fig. 2 left). This wetting transition is
droplet thus rests mostly on a cushion
of "The
air, visible as a thin ray of light between
the droplet and the solid substrate.
. FIG. 3: Bouncing droplets. (a) Conventional axisymmetric recoil of a water droplet hitting a
superhydrophobic silicon surface (top: side view, bottom: top view). (b) Non-axisymmetric recoil of
droplet on a macroscale textured surface (top: side view, bottom: top view). Pictures in (a-b) adapted
from [8]. (c) Side view of typical bouncing (top) and unconventional pancake bouncing (bottom) of
droplet on surface with tapered posts covered by nanoflowers. Picture from [9].
usually irreversible and the droplet becomes pinned
to the surface. To avoid the Wenzel state, we took guidance
from aquatic insects such as the water boatman
Notonecta glauca, that can breathe underwater thanks
to the air retention feature of their superhydrophobic
hairy exoskeleton. Barthlott et al. observed that
while aquatic insects with long hair can support a large
volume of air, insects with small hairy structures had
supreme lifetime of the air film, arguing that downward
progression of the air–water interface is hindered
due to the fact that it costs more energy to displace
an interface with a smaller radius of curvature [5].
We introduced a dual-level topography by coating a
standard, micropillared substrate with nanofilaments
(Fig. 2a, right) [6]. The pressure-induced collapse of
the standard "micro-Cassie" state now resulted in a
Wenzel-like state that has water between the micropillars,
and we call it "nano-Cassie" state because there remains
a nanoscopic air layer present keeping the wetted
solid fraction small. This allowed for a reversible transition
back to the original state by a small input of energy
in the form of suction. Recently, the Zheng group
even reported on fully reversible and spontaneous
(= energy input-free) transition on substrates with
suitable dual-level roughness (Fig. 2b, right) [7].
The otherwise irreversible wetting transition was
shown to be reversible on the dual-level surface.
Fluid dynamics of a bouncing droplet
The motion and fluid dynamics of droplets on superhydrophobic
surfaces can often be both striking and unexpected
(see example in Box 1). An exciting area of today's
research is in the bouncing of droplets off superhydrophobic
surfaces. Typically, the drops spread out nearly
axisymmetrically, retract and finally leave the surface (Fig.
3a). In doing so, there is a theoretical lower limit in the
required contact time between the drop and the solid.
One of the current challenges lies in finding new ways
to further reduce the contact time to allow for efficient
anti-icing and dropwise condensation applications. By
introducing macroscale texture to the substrate, the group
of Varanasi managed to break the axisymmetry involved
in bouncing (Fig. 3b), resulting in redistribution of liquid
mass, and thereby altering the hydrodynamics and
reducing contact time by a factor of four compared to
what has previously been considered the gold standard
[8]. In a clever approach by the Wang group [9], a superhydrophobic
surface was made of tapered, nanoflower-coated
pillars with characteristic dimensions one order
of magnitude larger than the conventional micropillared
design. Water drops with high enough inertia were shown
to spread out and then leave the surface without retracting
(Fig. 3c). This "pancake" bouncing also allowed for
a fourfold reduction in the contact time, compared to
conventional bouncing.
Slippery and never wet
During the last years, great advances have been made in deciphering
the physics behind superhydrophobicity. A fundamental
understanding of the intricate wetting characteristics
is being formed and novel ways to avoid wetting or utilize its
characteristics are explored. New exciting research avenues are
continuously being created to get one step closer to the superrepellent
materials of the future, revealing functions and features
that will greatly simplify and improve our everyday lives. n
About the authors
Matilda Backholm received her PhD in
2015 from McMaster University, Canada,
and is currently working as an Academy
of Finland postdoctoral researcher at
Aalto University.
Jaakko V. I. Timonen is professor of the
Active Matter group at Aalto University. He
received his PhD from the same university
in 2013 and did postdocs in the Grzybowski
and Aizenberg groups at Northwestern
University and Harvard, USA.
Robin H. A. Ras is professor of the Soft
Matter and Wetting group at Aalto University.
He received his PhD in 2003 from
the University of Leuven, Belgium, and was
awarded an ERC Consolidator grant in 2016.
[1] Purity of the sacred lotus, or escape from contamination in biological
surfaces, W. Barthlott and C. Neinhuis, Planta 202, 1 (1997).
[2] Mechanically durable superhydrophobic surfaces, T. Verho, C.
Bower, P. Andrew, S. Franssila, O. Ikkala, and R.H.A. Ras, Adv. Mater.
23, 673 (2011).
[3] Moving superhydrophobic surfaces toward real-world applications,
X. Tian, T. Verho, and R.H.A. Ras, Science 352, 142 (2016).
[4] How water advances on superhydrophobic surfaces, F. Schellenberger,
N. Encinas, D. Vollmer, and H.-J. Butt, Phys. Rev. Lett. 116,
096101 (2016).
[5] Dry Under Water: Comparative Morphology and Functional Aspects
of Air-Retaining Insect Surfaces, A. Balmert, H.F. Bohn,
P. Ditsche-Kuru, and W. Barthlott, J. Morphol. 272, 442 (2011).
[6] Reversible switching between superhydrophobic states on a hierarchically
structured surface, T. Verho, J.T. Korhonen, L. Sainiemi,
V. Jokinen, C. Bower, K. Franze, S. Franssila, P. Andrew, O. Ikkala,
and R.H.A. Ras, Proc. Natl. Acad. Sci. USA 26, 10210 (2012).
[7] Monostable superrepellent materials, Y. Li, D. Quéré, C. Lv,
and Q. Zheng, Proc. Natl. Acad. Sci. USA 114, 3387 (2017).
[8] Reducing the contact time of a bouncing drop, J.C. Bird, R.
Dhiman, H.-M. Kwon, and K.K. Varanasi, Nature 503, 385 (2013).
[9] Pancake bouncing on superhydrophobic surfaces, Y. Liu,
L. Moevius, X. Xu, T. Qian, J.M. Yeomans, and Z. Wang,
Nat. Phys. 10, 515 (2014).
[10] Switchable static and dynamic self-assembly of magnetic droplets
on superhydrophobic surfaces, J.V.I. Timonen, M. Latikka,
L. Leibler, R.H.A. Ras, and O. Ikkala, Science 341, 253 (2013).
Ferrofluids are colloidal dispersions of magnetic
nanoparticles in a carrier liquid. They exhibit a striking
coupling between fluidic and magnetic properties.
We asked ourselves a question: what kind of new
phenomena can be observed if the fascinating features
of ferrofluids are combined with the extreme non-wetting of
superhydrophobic surfaces?
We tested this experimentally by placing an aqueous
ferrofluid droplet on a superhydrophobic surface and
subjecting it to a gradually increasing vertical magnetic
field [10]. As a result, the shape of the droplet changed
from nearly perfectly spherical to elongated along the field
direction, until, spontaneously, the droplet split into two
smaller droplets (Fig. 4a and Movie youtu.be/ehvFFbFFsjg).
This splitting can be understood as the classic Rosensweig
instability taking place within the droplet and is driven by
the decrease of magnetic energy (at the expense of surface
energy). The role of the superhydrophobic surface is to
keep the droplets separated, and to allow for low-friction
droplet motion to their equilibrium positions. Further
increasing the magnetic field can lead to additional splitting
events and nearly a hundred droplets can easily be formed.
These droplets spontaneously assemble into well-defined
clusters due to mutual dipolar repulsion and interaction
with the spatially varying global confining magnetic field
(Fig. 4b). The magnetic droplets can be used as a model
system to study and visualize static and dynamic
self-assembly processes.
. FIG. 4: Magnetic droplets on superhydrophobic surfaces. (a) Profile of magnetic droplet
in a gradually increasing magnetic field (from left to right). (b) Hexagonal cluster of
19 daughter droplets formed by multiple consecutive splitting events from one single
mother droplet. The "lattice constant" can be tuned by adjusting the droplet-droplet
repulsion and confining external potential. Pictures adapted from [10].
llLuís O. Silva – Instituto Superior Técnico, Lisbon – DOI: https://doi.org/10.1051/epn/2017506
Laser technology has progressed tremendously since Theodore Maiman first
demonstrated the laser in 1960. One of the most striking examples of this progress
is the focused intensity of lasers. Present day lasers in the near infrared frequency
range can deliver intensities in excess of 10 23 W/cm 2 . Imagine that you have a
very large and powerful lens that captures the light of the sun hitting the upper
atmosphere of the Earth and focus it down to a region with the cross section of a
human hair. The corresponding intensity is in the range of the most intense lasers
now available.
Boiling the vacuum
nder the action of these intense electromagnetic
fields, electrons quiver at velocities close
to the speed of light with Lorentz gamma
factors ~100. The nonlinear effects associated
with special relativity determine the evolution of
light-plasma interactions at these intensities. These lasers
are now being explored to drive plasma accelerators [1,2],
or novel light sources [3].
The interplay between lasers, experiments, simulations,
and theory is well illustrated by the progress on
laser-plasma interactions. Ab initio simulations have been
at the core of plasma physics since the 50s, and this is
even more striking in laser-plasma accelerators (figure 1):
simulations, viewed as in silico experiments, have been
critical to interpret and to design many landmark experiments
on laser-plasma accelerators, and to predict the
directions for new facilities [4].
"Boiling the vacuum"
Even more intense lasers will be available in the near future,
such as the Extreme Light Infrastructure (ELI) [5].
As we move to even higher intensities the physics becomes
more rich and more complex [6], and quantum effects
m FIG. 1: The accelerating structure in a laser-plasma accelerator (iso-surfaces), also with the trajectories
of trapped and accelerated electrons, from low energies (blue) to high energy (red). Courtesy:
Samuel F. Martins
start to be important. A single ultra relativistic electron
quivering in an ultra intense laser field can radiate x-rays.
As the intensity is ramped up, the electron oscillating in the
laser field will radiate gamma-rays. These gamma-rays can,
in turn, interact with the laser and generate electron-positron
pairs which, in the presence of the laser field, can
again radiate strongly. An electromagnetic cascade of pairs
and gamma-rays is then triggered, generating a quantum
electrodynamic (QED) electron-positron plasma.
It is also possible to conceive scenarios where a static
(or slowly varying) ultra strong electric field is present
in a finite region of space. Let us imagine the field is so
strong that, as the electron is accelerated over the distance
of a Compton wavelength it gains more than 2 m e c 2 , i.e.
the rest mass energy of an electron and a positron. In this
case, an electron-positron pair is generated, which will
then interact with the ultra strong field itself, and a cascading
process can also be triggered. The critical electric
field for pair creation in vacuum, first identified by Sauter,
is called the Schwinger critical field E s = 2 π m e
c 3 /e h,
where e is the electron charge, m e the electron mass, h is
the Planck constant, and c the speed of light. For extreme
field physics a common used dimensionless parameter is
χ = E/E s , where E represents the electric field in the rest
frame of the electron. χ determines the transition from
the classical to the quantum dynamics; for χ on the order
or higher than unity, QED effects are important and
must be considered. Colloquially, when copious amounts
of electrons and positrons are produced by ultra strong
electromagnetic fields in vacuum, or via a cascade from
a low density seed of electrons, the "vacuum is boiling".
The prospect to reach in the laboratory these conditions
in the near future is triggering many exciting developments
[7, 8] at the cross roads of nonperturbative QED, plasma
physics, and astrophysics. In many extreme astrophysical
objects (e.g. pulsars, magnetars, or in the magnetosphere
b Optical trap: an
efficient converter of
light to matter. Four
lasers interact with
a thin wire of matter
(100x thinner than
a human hair). The
wire is trapped in
the vortexes of the
electric field and
radiates gammarays
that decay into
pairs. These pairs
are also trapped and
radiate gamma-rays.
The process continues
until most of the laser
energy converts to
matter (or gammarays). Courtesy:
Marija Vranic
Boiling the vacuum
m FIG. 2: Strong and weak scaling of OSIRIS, a state-of-the-art PIC code, for a typical production run in the
largest supercomputer in the world as of the time of the benchmark (2013) showing the measured speed-up
as a function of the number of processors up to more than 1 million cpu cores. Courtesy: Ricardo A. Fonseca
of black holes), pair production, electromagnetic cascades,
and strong radiation reaction are common processes that
have an important impact on the properties of the emitted
radiation. Therefore, understanding the interplay between
the fields and the particles is very important. This
renewed interest has also been an opportunity to revisit
seminal foundational works, such as the Heisenberg-Euler
semi-classical extension of Maxwell's equations, or the Bohr
postulate on the maximum possible physically achievable
electromagnetic intensity (see [9] for a discussion).
In silico QED plasmas
The underlying physics is highly nonlinear and depends
on the complicated and self-consistent trajectories of individual
charged particles in extreme electromagnetic
fields, including strong radiation dynamical effects, pair
. FIG. 3: OSIRIS simulation (the first ever) of three-dimensional QED cascades. Two laser pulses of opposite
circular polarisation collide, showing the cascade (electrons – red, positrons – green, gamma rays – yellow)
developing in the plane perpendicular to the laser propagation direction. Courtesy: Thomas Grismayer
production via QED processes, and, as soon as the cascades
develop or if a tenuous plasma is present, collective
plasma effects in complex field structures.
Although simplified analytical treatments are possible,
the complexity of the systems can only be captured with
computational modelling. The exponential developments
of high-performance computing have set "computer
simulations" as the third pillar of the scientific method,
complementing theory and experiments/observation.
For QED electron-positron plasmas in intense fields,
where laboratory experiments have limited reach, the
computational component has enhanced relevance, as
a probe of the dynamics of these complex systems, as a
tool to identify laboratory scenarios where bridges with
the physics of extreme astrophysical environments can
be established, or as a tool to model the global dynamics
of astrophysical objects and make connection with
observations. Therefore, the holistic comprehension of
these complex scenarios requires ab initio fully kinetic
simulations, following the trajectories of individual
particles, complemented by the relevant QED processes.
Plasma physics has a long tradition of kinetic simulations:
one of the first dynamical time dependent physical
models explored in computers was the one dimensional
plasma model, which opened the way to the particle-in-cell
(PIC) model [10]. The PIC model is one of the
most important computational tools in plasma and one
of the most effective possibilities to follow the self-consistent
dynamics of charged particles in electromagnetic
fields. In the PIC method the trajectories of a large number
of particles are solved self-consistently using forces
calculated from field equations solved on a grid. When
modelling plasmas, the field equations are the Maxwell's
equations for the electric and magnetic fields. PIC codes
are also used to study a broad set of topics, including accelerator
physics, cosmology, and semi-classical systems.
The numerical codes based on the PIC algorithm are
routinely used in some of the largest supercomputers in
the World (figure 2), and thus can fully take advantage
of the transformative nature that numerical simulations
are bringing to the 21 st century science.
It is not surprising then that a generalization of this
algorithm has been recently proposed [11-13] to explore
the extreme scenarios associated with the coupling of
QED with plasmas. These models are computationally
very demanding because the plasma scale is coupled with
the QED scale via a probabilistic event generator technique.
The possibility to take advantage of Peta floating
point operations per second (Petaflop/s) supercomputers
has already unveiled, even in the most simplified settings,
the richness of the physics, ranging from radiation
reaction effects in the collision of electron beams with
lasers, to the self-consistent evolution of electromagnetic
pair-plasma cascades, or the optimal configurations for
electromagnetic cascades
Boiling the vacuum
Exploring extreme plasma conditions
in the lab and in astrophysics
Ab initio simulations are already capturing the multidimensional
collision of multi GeV electron beams with
multi petawatt laser systems [14], showing this is an ideal
setting to explore the transition from classical radiation
reaction to quantum radiation reaction, associated with
the transition of a regime with low χ to χ ~1, opening
the way to test different models for radiation reaction.
Recent three dimensional simulations have also allowed
to determine the conditions for electromagnetic
cascades with ELI scale lasers [15], including the radiation
signatures and the properties of the associated gamma
ray source, and the dependence of these processes on
the configurations of the laser, taking into account the
polarization or multi-beam configurations.
From a plasma physics point of view, the interplay
between collective processes and QED effects associated
with very high fields is relevant in high charge electron
beam-electron/positron beam collisions, at the interaction
point, when beam disruption can be important.
Collective plasma processes are also important when the
density of the self-generated plasma due to the QED cascade
is so high that the plasma becomes opaque to the
laser itself. In this case there is strong light absorption
and efficient conversion of energy from the laser to the
pair plasma and the gamma rays [13].
What is more exciting is that many of the processes that
we are now exploring and understanding are at the core of
some of the most exciting astrophysical objects. In magnetars,
magnetic fields with magnitude close to the Schwinger
field are present and the interplay between the fields, the
plasma, and the QED processes remains an open question.
In the magnetosphere of pulsars, electromagnetic cascades
are also thought to be relevant. Global models for the magnetospheres
of pulsars have been recently implemented but
by coupling QED effects with the global geometry for the
fields in rotating magnetospheres, as illustrated in Figure
4, it will be possible to understand the global dynamics of
the system, determine radiation signatures, and identify
the physical processes that determine the radiation signatures
to mimic and further explore in the laboratory these
physical processes, thus understanding how the "vacuum
boils" in the laboratory and in astrophysics. n
I would like to thank R. Fonseca, T. Grismayer, M. Vranic,
F. Cruz, and everyone at the epp team at IST for discussions.
Work partially supported by the European Research
Council AdG2015 InPairs.
[1] C. Joshi, Scientific American 294 (2), 40 (2006)
[2] W. P. Leemans and E. Esarey, Physics Today 6 (3), 44 (2009)
[3] K. Ta Phuoc et al., Nature Photonics 6, 308 (2012)
[4] S. F. Martins et al., Nature Physics 6 (4), 311 (2010)
[5] https://eli-laser.eu
[6] G. A. Mourou, T. Tajima and S. V. Bulanov, Reviews of Modern
Physics 78 (2), 309 (2006)
[7] M. Marklund and P. K. Shukla, Reviews of Modern Physics 78 (2),
591 (2006)
[8] A. Di Piazza et al., Reviews of Modern Physics 84 (3), 1177 (2012)
[9] A. M. Fedotov et al., Physical Review Letters 105, 080402 (2010)
[10] J. M. Dawson, Reviews of Modern Physics 55 (2), 403 (1983)
[11] E. N. Nerush et al., Physical Review Letters 106, 035001 (2011)
[12] C. P. Ridgers et al., Physical Review Letters 108, 165006 (2012)
[13] T. Grismayer et al., Physics of Plasmas 23 (5), 05670 (2016)
[14] M. Vranic et al., Physical Review Letters 113 (13), 134801 (2014)
[15] T. Grismayer et al., Physical Review E 95 (2), 023210 (2017)
. FIG. 4: Ab initio simulation of a rotating magnetosphere showing the field lines of a centrifugally-driven
magnetosphere, with the spiralling features already present in the density, with plasma uniformly
loaded in the simulation region (projection in the top of the simulation box) Courtesy Fabio Cruz
About the Author
Luís O. Silva is Professor of Physics
at Instituto Superior Técnico, Lisbon,
PhD and Habilitation from IST, and
post-doc at UCLA (1997-2001). He was
awarded two ERC Advanced Grants,
among other prizes/honors. He is Fellow
of the APS, Global Young Academy, and the EPS.
A Tribute to Manne Siegbahn
llHenk Kubbinga – University of Groningen (The Netherlands) – DOI: https://doi.org/10.1051/epn/2017507
Spectroscopy came to dominate the 19 th century, with a crucial role for Swedish
physicists. It was Anders A ° ngström who introduced the tenmillionth part of a millimeter
as the wavelength unit (1868), a unit that was adopted by Rowland for his tables
of the solar spectral lines (1887-1893). Janne Rydberg, then, followed in A ° ngström's
footsteps in searching for relations between the emission spectra of the elements
and their place in the Periodic Table. Röntgen's new rays became a next challenge,
demanding a form of spectroscopy of their own. Manne Siegbahn, an assistant
of Rydberg, then, devised appropriate instruments of ever increasing precision.
Karl Manne Georg Siegbahn (1886-1978)
was born in Örebro, a city in Sweden's Lake
District. After graduation in 1906 he enrolled
at the University of Lund, where he
was charmed by the teachings of the mathematical
physicist Janne Rydberg (1854-1919). From Rydberg
he adopted a bent for the numerical relations between
the elements' spectral lines and their place in the Periodic
Table. In the year that Rydberg promulgated what
came to be known as the 2x 2 rule, with x (= 1 or 2)
as the ordinal index of the element at the Periodic
Table, Siegbahn came in. On 26 April 1911, then, he
passed the doctorate on a dissertation entitled Magnetische
Feldmessungen, which revealed his primarily
experimental propensity. In hindsight an unusually
short track indeed, since he made also time for two
trips abroad (1908, Göttingen; 1909, Munich). Physics'
Europe was in the making: in 1911 and 1914 new trips
followed, to Berlin, Heidelberg and Paris.
m FIG. 1: Manne Siegbahn by Bror Kronstrand (1936; oil on canvas, 50×60 cm; courtesy Gustavianum-
Uppsala University Museum). The original version was by Sam Uhrdain, 1928. Siegbahn's desk features
a self-devised X-ray tube in porcelain, for his high precision spectroscope.
From Barkla to Moseley; atomic
number versus atomic mass
In Munich, Siegbahn had made the acquaintance of
Arnold Sommerfeld and Max von Laue, who familiarized
him with the particularities of Röntgen's rays. This
domain lived a boost the moment, in June 1912, that
Laue, Friedrich and Knipping published their epochmaking
crystal-diffraction patterns. No wonder that
Siegbahn came under the spell of the new rays. The
Braggs subsequently introduced reflection instead of
diffraction, a technique that reduced the required time
significantly. For a while transverse waves, ether pulses
and particles lived side by side in the physicists' minds.
Laue's rather complex mathematics was exchanged,
by Bragg Jr., for a straightforward expression for the
A Tribute to Manne Siegbahn
difference in path length, lattice constant, and angle
of incidence:
nλ = 2d sinφ
with n = 1, 2, 3, ... No doubt, there was a highly energetic
electromagnetic radiation at issue, the wavelength of which
could now be calculated using the available data for the
crystal at stake. In case of rocksalt (NaCl) the mean distance
between the constituent atoms could be calculated from the
density (ρ = 2,17 g·cm –3 ), the molar mass (58,5 g), and the
constant N called after Avogadro: d = 2,814·10 –8 cm. With
φ = 11,55 and n = 1 the Braggs found λ = 1,78·10 –8 cm. In
October 1912, Henry Moseley, working under Rutherford
at Manchester, set out to check the results reported from
Munich and Cambridge. For a platinum anticathode he
found, in the spring of 1913, five wavelengths, in other
words, an emission spectrum consisting of five lines.
Simplicity itself, compared to the traditional emission spectra,
and therefore full of promises. Where others focused on
the rays themselves, Moseley weighted the consequences
for the ideas on atomic structure and its relation with the
Periodic System. There were reasons to believe that the ordering
principle of the System was not atomic mass, but
the positive charge of Rutherford's nucleus. Indeed, at least
three cases showed that the order did not always follow
atomic mass. Moseley, then, set out to study one of these, the
couple Co (Z = 27) and Ni (28). The idea was to study the
series Ca (20) through Zn (30), all metals ready to produce
sufficiently soft X-rays when used as anticathode material.
The pencil of rays was reflected by a crystal of potassium
ferrocyanide and detected, initially by a normal counter, but
later by a photographic plate. The results were unambiguous
in that the atomic number prevailed, as could be read out
from the shift of the two K-lines in question. There were also
less energetic lines, it appeared; following Barkla's system
(1907) they were known as L-lines. Barkla had weighted
the eventuality of even higher energetic lines, to be called
J, I, H, etc., but these never showed up.
X-ray-spectroscopy as such
In 1914, on the eve of the Great War, Manne Siegbahn
esteemed that the utility of X-ray spectra in the identification
of elements was obvious, even though the resolution
of the lines left much to be desired, not unlike the
precision in the wavelength determinations. While quite
a lot of his colleagues got fully involved in war activities,
Siegbahn could subsequently focus on the perfection of the
apparatus. Initially he used an instrument similar to that
of Moseley, that is, one in which a series of anticathodes
could be checked in a row (Fig.2). A first advance was the
integration of the reflecting crystal and the registration
unit in the discharge tube in view of reducing losses of
soft rays by absorption in the air. With his PhD-students
he showed, for zirconium and neodymium, that the
2 K-lines were in reality doublets, a fact that again stressed
the importance of precision. Next the scope of his research
was greatly widened to include also lighter elements. In
1916 new series—M and N—of longer wavelength showed
up. Siegbahn became the undisputed leader in the field.
Students from abroad, among whom Dirk Coster from
Leiden, flocked to Lund. In 1919 Siegbahn organized a
first post-War congress on the topic with Sommerfeld and
Bohr as key-notes; both were delighted to see their ideas
on atomic structure confirmed. No wonder that Siegbahn
was among the invités for the next Solvay Conference on
Physics, that of 1921, which was devoted to 'Atoms and
electrons'. In 1922 he moved on to the Faculty of Science
. FIG. 2: Moseley's set-up to produce soft Röntgen rays with anticathodes of various metals in an
evacuated tube. On the right, R is the rails (orthogonal to the paper), CT the carriage with the train
of metals to be investigated successively, S a slit, W gold-foil, B the table for the crystal and P the
photographic plate (from: Philosophical Magazine 1914).
A Tribute to Manne Siegbahn
of Uppsala University to continue his endeavours to bridge
the gap between the UV-part of the normal spectrum and
the X-rays. Rocksalt was exchanged for calcite, the X-unit
took the place of the Ångström, with 1 Å´ = 10 3 X.U. A monograph
entitled Spektroskopie der Röntgenstrahlen (1923,
1931; Fig.3) summarized the results of a new survey of the
relevant elements.
A retroactive Nobel-Prize
A rarety in the history of the Nobel Prize. For the Prize of
1924, 23 candidates had been nominated, none of whom
was deemed a worthy candidate in the light of Nobel's last
will, so the awarding was postponed. Siegbahn, then, was
among the nominees for 1925—for the first time—and
the Nobel Committee awarded him the still open Prize of
1924 "for his discoveries and research in the field of X-ray
spectroscopy". Among the nominators was Max von Laue
who, in his nomination letter dated 18 November 1924, had
stressed that Siegbahn was the one who had measured the
wavelengths in the Röntgen spectrum with such a precision
that by now the term scheme of Bohr's atomic theory could
be used with full confidence, allowing us even an insight in
the hitherto entirely dark structure of the heavier atoms.
From Swedish icon to global eminence
In the late 1920s the use of ruled gratings—first flat, later
concave, like those of Rowland—enabled the exact
b FIG. 3:
Spektroskopie der
. FIG. 4: Vacuüm flatgrating
for λ ≥ 10 4 X.U. as
devised by Siegbahn
et al. (1930; from
Spektroskopie der
1931, p.396). On the
left the X-ray tube
with the reflecting
crystal, in the
middle the grating
with a shutter,
on the right the
photographic plate.
determination of wavelengths and the introduction of an
absolute scale; very soft X-rays, then, came to be identified
with extreme UV light. Conversely, the lattice constant of
calcite could now be calibrated anew, leading to a more
precise value of Avogadro's constant. Early in the 1930s
Siegbahn's attention was drawn by the remarkable discoveries
in the field of nuclear physics, particularly the
confirmation, by Chadwick, of the existence of 'neutrons'
as postulated by Rutherford and their curious behaviour
as reported by Fermi. Sweden should also play a role in
all this, Siegbahn esteemed, and he argued for an entirely
new laboratory, at nearby Stockholm, under the
wings of the Swedish Academy of Sciences. With financial
support of the Wallenberg Foundation and the Swedish
Government he succeeded in creating, in 1937, a Nobel
Institute of Physics close to the Royal Swedish Academy
of Sciences. At the new institute powerful cyclotrons were
built, funded by the Wallenberg and Rockefeller Foundations.
From 1988 until 2011 it was known as the Manne
Siegbahn Institute of Physics and functioned under the
wings of the University of Stockholm. n
I am indebted to Karl Grandin (Royal Swedish Academy
of Sciences, Stockholm; Chair EPS-HoP-Group) for
kind permission to see the nomination letter by M. von
Laue and to Rolf Siemssen (University of Groningen)
for consultation. I am also obliged to Johanna Axnér and
Anna Hamberg of Uppsala University-Gustavianum for
archival assistance.
About the author
Henk Kubbinga is a historian of science
at the University of Groningen
and member of the EPS-HoP-Group.
Actually he is finishing the fifth and
last volume of The collected papers of
Frits Zernike.
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llZs. Fülöp, S. Biri and G. Lévai – MTA Atomki, Debrecen, Hungary – DOI: https://doi.org/10.1051/epn/2017508
The beginning of the 21 st century is characterised by several contradictions and
challenges. One of them is that scientific and technological development has never
been as important for the well-being of humankind as today. Nevertheless, these fields
seem to lose the attention of talented and interested youngsters.
It is thus in the interest of all of us in science to demonstrate
the beauties of scientific research to the young
generation. The classical methods do not seem to be
sufficient to complete this task, so new, innovative
techniques have to be developed to capture the attention
of the teenage generation.
The Miazma project was inspired by these ideas. Furthermore,
the course of events outlined above is especially
regrettable in Hungary, a country where physics
and natural sciences in general, have always been highly
valued. This is the reason why a group of physicists at
the Institute for Nuclear Research, Hungarian Academy
of Sciences (MTA Atomki), Debrecen [1] decided to
address high school age students directly, through their
preferred medium, a computer adventure game. It was a
long time ago, around the dawn of the personal computer
era, when the present authors were in the age group
of the targeted audience, so finding the right language
with the latter was a real challenge. In order to facilitate
the inter-generation communication, young colleagues,
practicing high school teachers, as well as junior family
members were asked to contribute to the efforts. The
key partner, however, was a professional company, Private
Moon Studios, that had extensive experience in
developing computer-based adventure games, as well
as tabletop and conventional strategic board games [2].
The director of this company was also a popular singer-songwriter
performing under the name Pierrot, and
this fact in itself helped to abolish the generation barrier
to the target audience.
Needless to say, scientists and artists contemplated
each other with some reservation during the early stage
of the project. The two groups couldn't have differed
more in their socialization, cultural background and
in general, in the way they looked at the world. We,
scientists, tried to resolve this shock jokingly, recalling
stories from the time of the Manhattan Project,
when two utterly different communities had to work
jointly to reach a common aim. Nevertheless, it soon
turned out that there are many common features in the
thinking of scientists and artists, and that the differences
also served as the source of mutual inspiration
for the two groups in overcoming difficulties. In the
end we all agreed that both science and developing
adventure games can be considered as special forms
of problem solving.
The story of Miazma [3] takes place in the present, but
refers back to several historical moments from the past
few hundred years. It contains both fictitious and realistic
elements. Fictitious are all the characters appearing in
the game in the present. However, the key characters of
the past, István Hatvani, the professor of the Reformed
College of Debrecen from the 18 th century, and Sándor
Szalay, the founding director of Atomki are real. The meteorite
that landed at Kaba, near Debrecen in 1857 is also
real, while the other meteorites playing role in the story
are fictitious.
From the technical point of view, Miazma is an
interactive film in the style of the "third person
point-and-click" adventure PC Windows games. In
other words, it is built of short film scenes embedded
in an interactive computer game environment.
Real locations are covered by live-action cinematic
approach, while the narrative depends on the actions
of the players themselves. Their decisions open
many possible alternative routes, all from a single
starting point towards one fixed ending. Besides the
film and the story, puzzles provide the main motivation
for players. In Miazma there are more than
30 puzzles, at varying levels of difficulty. Most of the
b P. 42: The fictitious
meteorite on
exhibition in the
AGORA Science
Centre, Debrecen
c FIG. 1: Jonathan
and the head of
the Radiocarbon
Laboratory, with
her beloved plants
and animals. This
laboratory is marked
by green colour in
the game to help
the orientation.
puzzles incorporate scientific problems (fictitiously)
created by Prof. Szalay several decades ago. According
to the story, these problems were designed
to be solvable only in a later age (the present), when
the necessary technology would become available.
With this, Prof. Szalay wanted to hide potentially
dangerous objects in his time, and guarantee that
they would be handled by trustable individuals -
scientists of the 21 st century. In working out the details
we tried to keep scientific rigour at a sufficiently
high level. However, compromise was made at several
instances in order to make the storyline more fluent.
In the starting scene, a journalist, Jonathan Hunt arrives
at Atomki, where he meets a young physicist, Vera.
In her office the player can practice the controls of the
game (selecting objects, using the inventory etc.). Jonathan's
visit soon turns into an investigation for a missing
teenage boy Balázs, Vera's younger brother. The characters
of Jonathan (who already appeared in other adventure
games) and Balázs represent the experienced detective
and the curious teenager, whom the players can identify
with during the game.
Edutainment: The process of entertaining people at the
same time as you are teaching them something, and the
products, such as television programmes or software, that
do this. (Cambridge Business English Dictionary, Cambridge
University Press)
Miasma: A vaporous exhalation formerly believed to cause
disease. (Merriam-Webster Dictionary)
Miazma: A new edutainment PC computer game developed in
MTA Atomki, Debrecen, Hungary.
Jonathan starts the investigation by visiting the laboratories
of the institute. For a better identification, each laboratory
has a specific colour and decoration (see Fig. 1.).
Furthermore, each scientist has some hobby, which also
turns out to be useful in solving the puzzles. The following
laboratories are shown and visited (some named slightly
differently in the game):
Surface Science Laboratory
Ion beam Analysis Laboratory
Computer Centre
Cyclotron Control Room
Plasma Physics Laboratory
Radiochemistry Laboratory
Radiocarbon Laboratory
During this stage Jonathan (and the player) gets the
first impressions of the activities of the laboratories and
the technologies available there.
The investigation also extends beyond the gates of the
institute to the city of Debrecen, revealing some of its
rich cultural heritage. It is at the visit to the Reformed
College [6] when a meteorite first comes into the picture
(Fig. 2.). Further pieces of information about the missing
boy are collected in the College library, in an old church
and in an observatory.
Meanwhile, the boy tries to escape from an underground
labyrinth of cellars (Fig. 3). From this point, the storyline is
temporarily no longer linear; we can follow both his escape
and the investigation. In the labyrinth, common tools are to
be combined and used with the laws of physics to open the
next door and move on. These cover standard high-school
physics topics, including mechanics, thermodynamics, electricity
etc. A booklet is at hand to help the player, written in
the style of the 1960's, in the form of a dialogue between a father
and his 10-year-old son, on everyday aspects of physics.
Finally, Jonathan's investigation reveals a secret safe
in the director's office, well hidden by Professor Szalay
decades before (Fig. 4). He obviously wanted to leave important
messages to posterity. There are six combination
locks on the safe, and a small chest with six corresponding
compartments, each containing "coded messages". Using
these messages (usually a set of small objects or enigmatic
notes), Hunt relies on the assistance by the laboratories
again in finding the combinations for the locks. From
this point, the player can proceed in any order, visiting
any of the labs or returning anywhere later. Solving the
puzzles often requires objects or information obtained
at another location earlier. The six puzzles are based on
the following objects and physical methods:
1. Lapis lazuli in small bottles: element analysis and
date labelling
2. Rubber bell and a bone flute: sound frequency calculation
and measurement
3. Old gold-plated coin: multiple thin layers, depth analysis
4. Picture of a rainbow: plasmas from noble gases, wave
5. Lead box with radioactivity sign on it: irradiation with
cyclotron beam, PET camera study
6. A ring and a clock face: the Szalay-Csikai neutrino
experiment in 1956 [4]
With the help of the scientists, Jonathan Hunt (and
the player) figures out the next step needed to proceed
with the puzzles. In this scientific investigation he uses the
instruments, methods and knowledge de facto available
in Atomki.
Finally all the puzzles are solved and the safe opens!
Of course we cannot reveal what is found there and
what is the end of the story. Instead, we encourage the
readers to play the game and enjoy the thrill of science
and adventure.
The game is a result of the long-term evolution of
Atomki's outreach activities and its collaboration with
high school teachers of the city. The Hungarian version
of Miazma was a standalone project co-financed
by the European Social Fund (grant agreement no.
TÁMOP-4.2.3-12/1/KONV-2012-0057) and distributed
in DVD format to the readers of a major science magazine
in Hungary, available in all high school libraries.
Recently, we have provided free download of the game
for the entire Hungarian community. The Agora Science
Centre of Debrecen [7] visited by thousands per year
provides a special exhibition space for Miazma, where
visitors can not only play the game, but also see the mysterious
meteorite and the safe as well. The scene in which
Balázs escapes from the labyrinth was also reconstructed
temporarily for a science summer school, where many
visiting students had the opportunity to test their skills
in a realistic situation.
The Reformed College of Debrecen, founded in 1538, has
always been the symbol of the Calvinist tradition of Debrecen.
The college played a major role in the cultural and religious
life of Hungary for centuries. Many famous Hungarian writers,
poets, as well as scientists studied there. The college had
strong links with universities in Switzerland, Germany and
Holland: numerous graduates of the college visited these
institutes, and on returning home, promoted the modern ideas
learned there. The rich collection of the College Library also
dates back to the time of these "peregrines'', whose donations
were essential in enlarging it. One of the most renowned
professors of the College was István Hatvani (1718-1786), who
studied mathematics, physics and medicine in Basel, Utrecht
and Leiden. He refused the invitation for professorship in
Leiden, and returned to Debrecen to become professor of the
Reformed College. He had an extensive teaching activity, but
he was most renowned for his experiments with electricity,
earning him the title "Hungarian Faustus''.
m FIG. 2: Collecting information in the library of the Reformed College.
Founded in 1954, the Institute for Nuclear Research (MTA
Atomki) belongs to the network of research laboratories
administered by the Hungarian Academy of Sciences. The
founding director Sándor (Alexander) Szalay (1909-1987)
studied nuclear physics in Cavendish Laboratory, Cambridge,
where he worked with Nobel Laureate Lord Ernest Rutherford.
In 1956, together with his Ph.D. student, J. Csikai, he performed
a cloud chamber experiment that indirectly proved the
existence of (anti)neutrino in the beta-decay of 6 He. For this
achievement Atomki was declared EPS Historic Site in 2013 [4].
Atomki has developed into a national accelerator centre, where
about 110 researchers work in nuclear, atomic and particle
physics, as well as in environmental science. The present
research policy of Atomki follows the interdisciplinary approach
always characterizing the institute [5].
The international version was presented first at the
10 th edition of the Science on Stage Festival in Debrecen,
2017 attended by more than 400 science teachers from all
over Europe [8]. The international version of the game,
however, is not public domain. It can be downloaded
from the Atomki web page [9] and limited number of
activation codes can be requested from the sponsors of
the game: the European Physical Society [10], the Nuclear
Physics European Collaboration Committee (NuPECC)
[11] and the ENSAR2 European project [12] through
the European Union's Horizon 2020 research and innovation
programme under grant agreement No 654002.
Negotiations are under way with major gaming download
sites, e.g. STEAM, to make the game available on
the European market.
As an epilogue, one may wonder whether one can
really learn physics from adventure game based on a science
related story. Maybe not. However, and this is the
firm belief of the authors, it can help to feel the thrill of
scientific investigation, to appreciate the power of hightech
instruments and, eventually, to understand the importance
of evidence based research. n
m FIG. 3: Escaping from
the underground
. FIG. 4: The hidden
safe with six
combination locks.
[1] www.atomki.hu/en/
[2] http://gamedev.privatemoon.com/en
[3] https://youtu.be/ItF3kHGO5MY
[4] R. G. Lovas, Europhysics News 45/1, 04 (2014)
[5] Zs. Fülöp and G. Lévai, Nuclear Physics News 25/4,
05 (2015)
[6] https://en.wikipedia.org/wiki/Debrecen_Reformed_
[7] http://www.agoradebrecen.hu/en/
[8] http://sons2017.eu/
[9] www.atomki.hu/miazmaeng
[10] http://www.eps.org/
[11] http://www.nupecc.org/
[12] http://www.ensarfp7.eu/
About the Authors
Zsolt Fülöp is scientific adviser at
MTA Atomki working in the field of
nuclear astrophysics. Former chair of
the EPS Nuclear Physics Division and
former member of the EPS Executive
Sándor Biri is senior researcher at
MTA Atomki. His research interest
is atomic plasmas, ion sources and
accelerators R/D. He is presently
the head of the Accelerator Center
of Atomki.
Géza Lévai is scientific adviser at
MTA Atomki. His field of interest is
symmetry-related studies in quantum
mechanics and theoretical nuclear physics.
Presently he is the deputy director
of Atomki.
Private Moon Studios [2] is an independent Hungarian
game developer company specialized in computer games,
board games and touristic games. They developed a range
of interactive city adventure games, offering an opportunity
to learn about the historic sights of a city in the course of
an exciting investigation. The first interactive movie game
of the company was Yoomurjak's Ring, the first in the line of
Jonathan Hunt Adventures. The game's deep storyline has been
subsequently extended into a novel. The protagonist, Jonathan
Hunt is a young journalist from New York who has Hungarian
ancestry. His first trip to Hungary begins as innocently as a
vacation in the city of Eger, but soon turns into a treasure hunt
for a mysterious ring and hidden messages from the past.
The game features real-life locations to be discovered virtually
and an immense amount of movie footage, pictures and
panoramic photos.
Backholm M. Slippery and never wet•
48/5&6 • p.30
Bažant Z.P.
see Le J.-L.
Beijerinck H.C.W. Gender diversity in
STEM• 48/2 • p.16 | NatLab, Eindhoven,
The Netherlands• 48/5&6 • p.04
Benedikt M. Can we afford to wait?
Designing the collider of the future
• 48/4 • p.12
Biri S.
see Fülöp Zs.
Bosman M. International Day of Women
and Girls in Science • 48/2 • p.05
Bracco A. The NuPECC Long Range Plan
2017: Perspectives in Nuclear Physics
• 48/4 • p.21
Braun H.H. Inauguration and first beam
of PSI's X-ray FEL SwissFEL • 48/1 • p.05
Buzdin A. See Mukhin S.
Caux J.-S. Redressing the inverted pyramid
of scientific publishing • 48/5&6 • p.25
Cifarelli L. The remake of an iconic photo
• 48/5&6 • p.10
Crabtree G. Where is transportation
going? • 48/3 • p.21
Dalnoki-Veress K. see Salez T.
Daruka I. Publication stock exchange
(PSX) • 48/1 • p.28
De Natale G. Reale Osservatorio Vesuviano,
Herculaneum (Naples), Italy • 48/1 • p.06
Dulieu O. Ion Coulomb crystals: from
quantum technology to chemistry close
to the absolute zero point • 48/2 • p.17
Duff M. A lesson for the future of our
science: my testimony on Lord Patrick
M.S. Blackett • 48/3 • p.32 | Piersanti
Mattarella, Tower of Thought - Erice, Sicily,
Italy • 48/2 • p.04
Fatta-Kassinos D. see Fernàndez-Ibañez P.
Ferdinande H. see Pohl M.
Fernàndez-Ibañez P. Can solar watertreatment
really help in the fight against
water shortages? • 48/3 • p.26
Formosa-Gauci C. Pioneering
SESAME light source circulates first beam
• 48/1 • p.08
Forrest J.A. see Salez T.
Fülöp Zs. Miazma: physics edutainment
through a computer game • 48/5&6 • p.42
Heinz A.M. Uddmanska House, Kungälv,
Sweden • 48/1 • p.04
Hermans L.J.F. (Jo) Fascinating friction
• 48/5&6 • p.29 | Physics formulas on
Leiden walls • 48/1 • p.07 | Travel with
hydrogen • 48/2 • p.32
Jonson B.
see Heinz A.M.
Kalda J. First European Physics Olympiad
• 48/4 • p.04
Klein T. Ring lasers – a brief history
• 48/4 • p.25
Kleijn A.W. Vacuum Science and
Technology • 48/4 • p.32
Kocs E. see Crabtree G.
Kubbinga H. A Tribute to Manne
Siegbahn • 48/5&6 • p.38
Kundt W. Letter to the Editors • 48/3 • p.25
Le J.-L. Mechanics-based mathematical
studies proving spontaneity of postimpact
WTC towers collapse • 48/1 • p.18
Lee D. EPS gears up for 50 th Anniversary •
48/5&6 • p.06
Lévai G. see Fülöp Zs.
Marino A. Britain's nuclear secrets: inside
Sellafield • 48/5&6 • p.21
McGraw J.D. see Salez T.
McGuigan K.G. see Fernàndez-Ibañez P.
Mischke A. International conference on
Strangeness in Quark Matter in Utrecht
• 48/5&6 • p.11
Mukhin S. Alexei Abrikosov (1928-2017)
• 48/3 • p.06
Neugart R. Properties of nuclei probed
by laser light • 48/2 • p.12
Ongena J. A primer on energy from
nuclear fission • 48/1 • p.30
Pázsit I.
see Heinz A.M.
Pohl M. In memoriam: Prof. em. Dr. Ernst
Heerr • 48/4 • p.07
Poitou J. A brief tour of the climate
machine 1 - The Climate machine, a two
fluids thermal engine • 48/2 • p.26 |
2 - Environment shapes the climate
• 48/3 • p.17
Raphaël E. see Salez T.
Ras R.H.A. see Backholm M.
Ritzmann U. Why should one become
involved in EPS Young Minds? • 48/1 • p.32
Rossel C. An open and peaceful world
for Science • 48/1 • p.03 | Scientific and
ethical responsibility • 48/2 • p.03
Salez T. Glass transition at interfaces
• 48/1 • p.24
Sauer P. see Pohl M.
Saunders F. Research Ethics and Research
Integrity – Why it matters • 48/4 • p.06
Sakellariadou M. Gravitational Physics:
the birth of a new era • 48/5&6 • p.18 |
Nobel prize in physics 2017 • 48/5&6 • p.08
Silva L.O "Boiling the vacuum": in silico
plasmas under extreme conditions in the
laboratory and in astrophysics • 48/5&6 • p.34
Sjøberg S. PISA testing – a global
educational race? • 48/4 • p.17
Sólyom J. In memoriam: Prof. Alfred
Zawadowski • 48/5&6 • p.09
Selten T. Stella Lux: the energy-positive
family car • 48/3 • p.13
Tillman B. see Crabtree G.
Timonen J.V. see Backholm M.
van der Steenhoven G. Trump, climate
change and the EPS • 48/1 • p.28
Varlamov A. See Mukhin S.
von Toussaint U. Data Analysis: a (not so)
silent revolution • 48/1 • p.15
Voss R. Challenging times for the EPS • 48/3
• p.03 | Election day • 48/4 • p.03 | Working
together on the evidence base • 48/5 • p.03
Willitsch S. see Dulieu O.
Yeomans J.M. Nature's engines: active
matter • 48/2 • p.21
Zaránd G. see Sólyom J.
Zimmermann F. see Benedikt M.
volume 48 - 2017
Annual index
Volume 48 - 2017 • 47/5&6 • p.47
Book review
A lesson for the future of our science:
my testimony on Lord Patrick M.S.
Blackett Duff M.
A primer on energy from nuclear fission
Ongena J.
Vacuum Science and Technology
Kleijn A.W.
Crossing borders
Gender diversity in STEM
Beijerinck H.C.W.
Publication stock exchange (PSX)
Daruka I.
An open and peaceful world
for Science Rossel C.
Challenging times for the EPS Voss R.
Election day Voss R.
Scientific and ethical responsibility
Rossel C.
Working together on the evidence
base Voss R.
First European Physics Olympiad Kalda J.
International conference on Strangeness
in Quark Matter in Utrecht
Mischke A.
Everyday physics
Ring lasers – a brief history Klein T.
Historic sites
NatLab, Eindhoven, The
Netherlands Beijerinck H.C.W
Piersanti Mattarella, Tower of Thought -
Erice, Sicily, Italy Duff M.
Reale Osservatorio Vesuviano, Herculaneum
(Naples), Italy De Natale G.
Uddmanska House, Kungälv, Sweden
Heinz A.M., Jonson B. and Pázsit I.
48/1 • 13 summaries • p. 09-14
48/2 • 14 summaries • p. 06-11
48/3 • 11 summaries • p. 08-12
48/4 • 08 summaries • p. 08-11
48/5&6 • 12 summaries • p. 12-18
A brief tour of the climate machine
1 - The Climate machine, a two fluids
thermal engine Poitou J.
2 - Environment shapes
the climate Poitou J.
A Tribute to Manne Siegbahn Kubbinga H.
"Boiling the vacuum": in silico plasmas under
extreme conditions in the laboratory
and in astrophysics Silva L.O.
Britain's nuclear secrets: inside Sellafield
Marino A.
Can solar water-treatment really
help in the fight against water
shortages? Fernàndez-Ibañez P.,
McGuigan K.G. and Fatta-Kassinos D.
Can we afford to wait? Designing the
collider of the future Benedikt M.
and Zimmermann F.
Data Analysis: a (not so) silent revolution
von Toussaint U.
Glass transition at interfaces
Salez T., McGraw J.D., Dalnoki-Veress
K., Raphaël E. and Forrest J.A.
Gravitational Physics: the birth
of a new era Sakellariadou M.
Ion Coulomb crystals: from quantum
technology to chemistry close to the
absolute zero point Dulieu O.
and Willitsch S.
Mechanics-based mathematical studies
proving spontaneity of post-impact
WTC towers collapse Le J.-L. and
Bažant Z.P.
Miazma: physics edutainment through
a computer game Fülöp Zs., Biri S.
and Lévai G.
Nature's engines: active matter
PISA testing – a global educational
race? Sjøberg S.
Yeomans J.M.
Properties of nuclei probed by laser light
Neugart R.
Redressing the inverted pyramid
of scientific publishing Caux J.-S.
Slippery and never wet Backholm M.,
Timonen J.V. I. and Ras R.H.A.
Stella Lux: the energy-positive
family car Selten T.
The NuPECC Long Range Plan
2017: Perspectives in Nuclear
Physics Bracco A.
Where is transportation going?
Crabtree G., Kocs E. and Tillman B.
Inside EPS
Call for Nominations, President-elect • 48/4 • p.05
EPS directory • 48/4 • p.29
EPS gears up for 50 th Anniversary Lee D.
Highlights from EPS Council • 48/3 • p.04
Letter to the Editors Kundt W.
Alexei Abrikosov (1928-2017)
Mukhin S., Varlamov A. and Buzdin A.
In memoriam: Prof. Alfred Zawadowski
Sólyom J. and Zaránd G.
In memoriam: Prof. em. Dr. Ernst Heer
Pohl M., Ferdinande H. and Sauer P.
Trump, climate change and the EPS
van der Steenhoven G.
Why should one become involved in EPS
Young Minds? Ritzmann U.
Physics and Society
International Day of Women and Girls
in Science Bosman M.
Research Ethics and Research Integrity –
Why it matters Saunders F.
The remake of an iconic photo Cifarelli L.
Physics in daily life
Fascinating friction
Travel with hydrogen
Hermans L.J.F. (Jo)
Prizes - Awards - Medals
Nobel prize in physics
2017 Sakellariadou M.
Hermans L.J.F. (Jo)
Dieter Meschede becomes president
of the German Physical Society from 2018
to 2020 • 48/4 • p.07
Physics formulas on Leiden walls
Hermans L.J.F. (Jo)
Inauguration and first beam of PSI's X-ray
FEL SwissFEL Braun H.H.
Pioneering SESAME light source circulates
first beam Formosa-Gauci C.
Pioneering SESAME light source officially
opened • 48/3 • p.07