Fluctuations at Phase Transitions
  We use the closed time-path formalism to calculate fluctuations at phase transitions, both in and out of equilibrium. Specifically, we consider the creation of vortices by fluctuations, of relevance to the early universe and to $^{4}He$ superfluidity. (Invited talk to Nato Advanced Research Workshop on Electroweak Physics and the Early Universe, Sintra (Portugal), March 1994) 
R.J. Rivers