General complex Spin Weak Values obtained in Matter-Wave Interferometer   Experiments
  Weak values of the spin operator Sz of massive particles, more precisely neutrons, have been experimentally determined by applying a novel measurement scheme. This is achieved by coupling the neutron's spin weakly to its spatial degree of freedom in a single-neutron interferometer setup. The real and imaginary parts as well as the modulus of the weak value are obtained by a systematical variation of pre- and post-selected ensembles, which enables to study the complex properties of spin weak values. 
Stephan Sponar and Tobias Denkmayr and Hermann Geppert and Hartmut   Lemmel and Alexandre Matzkin and Yuji Hasegawa
quant-ph