Time Evolution of Non-Equilibrium Effective Action
  The time evolution of correlation functions in statistical systems is described by an exact functional differential equation for the corresponding generating functionals. This allows for a systematic discussion of non-equilibrium physics and the approach to equilibrium without the need of solving the nonlinear microscopic equations of motion or computing the time dependence of the probability distribution explicitly. 
Christof Wetterich (ITP, U Heidelberg)