SpaceTime quantum quenches 

Mario Collura 
propriomario AT tiscali DOT it 
Laboratoire de Physique des Matériaux (Nancy 1) 

le Thursday 05 November 2009 à 14h30 
Institut für Theoretische Physik, large seminar room. 


We consider a quantum system with a powerlaw deviation from the critical couplings such that the system is critical at its surface. We study the temporal behaviour of a such system under a slow powerlaw quench which drives the system through a second order quantum phase transition. Using scaling arguments we show that around the critical locus (put in x=0,t=0) appears a crossover region with spatial lenght λ and temporal lenght τ that scale with the adiabaticity rate v as a power related either to the critical exponents z an ν characterizing the phase transition and to the exponents ω and α characterizing the spatial deviation of the couplings and the temporal quench, respectively. We support general scaling arguments by applying the trapsize scaling in the framework of the adiabatic perturbative expansion. We supplement our results with both analytical and numerical studies of the Ising quantum chain. 
