Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

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

TT 19.6: Talk

Monday, March 16, 2015, 16:15–16:30, H 3010

Dynamical Quantum Phase Transitions in the Kitaev Honeycomb Model — •Markus Schmitt and Stefan Kehrein — Institut für Theoretische Physik, Georg-August-Universität Göttingen, Germany

The notion of a dynamical quantum phase transition (DQPT) was recently introduced by Heyl et al. as the non-analytic behaviour of the dynamical free energy at critical times in the real time evolution of quantum systems in the thermodynamic limit [Heyl et al., Phys. Rev. Lett., 110:135704, 2013]. We present results for the quench dynamics in the vortex-free sector of the two-dimensional Kitaev honeycomb model, which can be mapped to BCS-form, regarding the occurrence of DQPTs. For general two-dimensional systems of BCS-type the zeros of the dynamical partition function coalesce to areas in the thermodynamic limit and DQPTs are of second order. In the Kitaev honeycomb model these DQPTs occur after quenches across a phase boundary or within the massless phase. Considering the 1d limit of the Kitaev honeycomb model it becomes clear that the higher order of the DQPTs is intimately related to the higher dimensionality of the non-degenerate model. Moreover, a conjectured connection between the appearance of DQPTs and ergodicity, which becomes manifest as a relation between the long time limit of the dynamical free energy and the fidelity, is found to hold for the Kitaev honeycomb model.