DOMAIN-WALL FORMATION IN THE POST-INFLATIONARY UNIVERSE

We consider the evolution of the probability distribution P(chi, chiBA R, t), associated with an inhomogeneous light scalar field chi in the Robertson-Walker Universe, where the inhomogeneities are produced by q uantum fluctuations during an earlier inflationary epoch. For a specif ic choice of scalar potential which occurs in models of so-called late -time phase transitions in which domain walls are produced, P is shown to evolve from a gaussian to a non-gaussian distribution. The structu re of the latter justifies the recent use of three-dimensional percola tion theory to describe the initial distribution of domain walls in th ese models.