Leticia Cugliandolo (Professeur, Université Paris Pierre et Marie Curie) - jeudi 20 mars 2014.
When a dissipative macroscopic system is driven through a second order phase transition (a quench) it undergoes an ordering process, usually called phase ordering. During this process topological defects (be them domain walls, vortices or other) tend to disappear. In this talk I will focus on the time and quench-rate dependence of the number density of topological defects in systems with scalar and vector order parameter. Typical examples of the former are Ising ferromagnets and of the latter are superfluids or superconductors. By combining scaling and numerical analysis I will show that the typical growing length of ordered regions determines the density of topological defects left over in the symmetry broken phase, far from the critical region, and that this is much lower than the one predicted by the Kibble-Zurek mechanism.
You can also watch this video on the multimedia site ENS :savoirs.ens.fr