Vortices and the Ginzburg-Landau phase transition
  The methods for studying the role of vortex loops in the phase transition of the Ginzburg-Landau theory of superconductivity using lattice Monte Carlo simulations are discussed. Gauge-invariant observables that measure the properties of the vortex loop distribution are defined. The exact relations between the lattice and continuum quantities make it possible to extrapolate the results of the simulations to the continuum limit. The relationship between spontaneous symmetry breaking and phase transitions is also reviewed, with an emphasis on the fact that a local symmetry cannot be broken. 
A. Rajantie (Helsinki Institute of Physics)