X iv : h ep - p h / 98 02 22 9 v 1 3 F eb 1 99 8 DART - HEP - 97 / 07 – December 1997 Two Lectures on Phase Mixing 1

The dynamics of phase transitions plays a crucial rôle in the socalled interface between high energy particle physics and cosmology. Many of the interesting results generated during the last fifteen years or so rely on simplified assumptions concerning the complex mechanisms typical of nonequilibrium field theories. After reviewing well-known results concerning the dynamics of first and second order phase transitions, I argue that much is yet to be understood, in particular in situations where homogeneous nucleation theory does not apply. I present a method to deal with departures from homogeneous nucleation, and compare its efficacy with numerical simulations. Finally, I discuss the interesting problem of matching numerical simulations of stochastic field theories with continuum models. Invited lectures for “Field Theoretical Tools in Polymer and Particle Physics”, Wuppertal, June 17-19 1997. NSF Presidential Faculty Fellow Permanent address