  In many inflationary models, a large amount of energy is transferred rapidly
to the long-wavelength matter fields during a period of preheating after
inflation. We study how this changes the dynamics of the electroweak phase
transition if inflation ends at the electroweak scale. We simulate a classical
SU(2)xU(1)+Higgs model with initial conditions in which the energy is
concentrated in the long-wavelength Higgs modes. With a suitable initial energy
density, the electroweak symmetry is restored non-thermally but broken again
when the fields thermalize. During this symmetry restoration, baryon number is
violated, and we measure its time evolution, pointing out that it is highly
non-Brownian. This makes it difficult to estimate the generated baryon
asymmetry.
