Defect formation in inhomogeneous second-order phase transition: theory and experiment

The status quo in our understanding of defect formation during a rapid tran sition into the broken symmetry state in condensed matter and cosmology is discussed. An observation of vortex nucleation in neutron absorption experi ments in superfluid He-3-B is interpreted in terms of defect formation duri ng inhomogeneous cooling through T-c. Due to the temperature gradient in th e locally heated region the superfluid-phase transition occurs as a propaga ting front. The theoretical considerations of vortex formation at the propa gating front are based on works by Kibble-Volovik, Kopnin-Thuneberg, and Ar anson-Kopnin-Vinokur (AKV). (C) 2000 Elsevier Science B.V. All rights reser ved.