## Fast and slow quenches across second order phase transitions : the morphology of structures and the density of topological defects

When a dissipative macroscopic system is driven through a second order phase transition (a quench) it undergoes an ordering process, usually called phase ordering. Typically, during this process, spatial regions with the order of the (competing) equilibrium phases increase in size and topological defects (be them domain walls, vortices or other) tend to disappear.

In this talk I will discuss the morphological and statistical properties of ordered structures along coarsening in a paradigmatic dynamic universality class (the one of non-conserved scalar order parameter, such a Ising ferromagnets). I will also discuss the time and quench-rate dependence of the number density of topological defects in systems with scalar and vector order parameter. 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.