Starts 9 Jun 2009 13:00
Ends 9 Jun 2009 20:00
Central European Time
Leonardo da Vinci Building Seminar Room
Strada Costiera, 11 I - 34151 Trieste (Italy)
We numerically study the adiabatic quantum dynamics of an anisotropic spin-1 XY chain across a second order quantum phase transition. The system is driven out of equilibrium by performing a quench on the uniaxial single-spin anisotropy, that is supposed to vary linearly in time. We focus on the behavior of the excess energy, which quantifies the loss of adiabaticity of the system during the evolution. For small system sizes only the ground state and the first excited state effectively participate in the evolution, so the dynamics can be explained in terms of a Landau-Zener model, which describes an avoided level crossing between two levels. For sufficiently large system sizes, the excess energy after the quench admits a non trivial scaling behavior that is not predictable by standard Kibble-Zurek arguments for isolated critical points or extended critical regions. This emerges from a competing effect of many accessible low-lying excited states, inside the whole continuous line of critical points.