Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: Correlated Electrons: Nonequilibrium Quantum Many-Body Systems 2 (jointly with DY)

TT 19.8: Vortrag

Montag, 16. März 2015, 17:00–17:15, H 3010

Dynamical phase transitions in the mean field Ising model — •Ingo Homrighausen and Stefan Kehrein — Institut für Theoretische Physik, Georg-August-Universität Göttingen, Germany

The complexity of quantum many body physics leads to interesting phenomena far from equilibrium. An accessible quantity that characterizes the non-equilibrium quantum dynamics after a quantum quench is the return probability (Loschmidt echo). Dynamical phase transitions (DPTs) are defined as non-analyticities in the time-dependence of the return probability rate function in the thermodynamic limit. These DPTs were first observed in the one dimensional transverse-field Ising model for quenches across the quantum critical point [1]. Thereafter they have been studied mostly in low-dimensional exactly solvable models. We investigate the existence of DPTs in the infinite-dimensional mean field limit of the transverse-field Ising model. Now, in contrast to the one-dimensional case, DPTs occur for quenches across the equilibrium phase boundary as well as for quenches within the ordered phase. Moreover, in addition to the non-analytic behavior of the return probability we also find non-analyticities in the rate function of the work distribution for non-zero work. Based on a semiclassical analysis we explain the mechanism behind our findings.

[1] Heyl et al., Phys. Rev. Lett. 110, 135704 (2013)