Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 81: Nonequilibrium Quantum Many-Body Systems III
TT 81.1: Vortrag
Donnerstag, 15. März 2018, 09:30–09:45, H 3010
Dynamical Quantum Phase Transitions in Systems with Continuous Symmetry Breaking — •Simon Weidinger1, Markus Heyl2,1, Alessandro Silva3, and Michael Knap1 — 1Department of Physics and Institute of Advanced Study, Technical University of Munich, 85748 Garching, Germany — 2Max-Planck-Institute für Physik komplexer Systeme, 01187 Dresden, Germany — 3SISSA - International School for Advanced Studies, via Bonomea 265, 34136 Trieste, Italy
Interacting many-body systems that are driven far away from equilibrium can exhibit phase transitions between dynamically emerging quantum phases, which manifest as singularities in the Loschmidt echo. Whether and under which conditions such dynamical transitions occur in higher-dimensional systems with spontaneously broken continuous symmetries is largely elusive thus far. Here, we study the dynamics of the Loschmidt echo in the three dimensional O(N) model following a quantum quench from a symmetry breaking initial state. The O(N) model exhibits a dynamical transition in the asymptotic steady state, separating two phases with a finite and vanishing order parameter, that is associated with the broken symmetry. We analytically calculate the rate function of the Loschmidt echo and find that it exhibits periodic kink singularities when this dynamical steady-state transition is crossed. The singularities arise exactly at the zero-crossings of the oscillating order parameter. As a consequence, the appearance of the kink singularities in the transient dynamics is directly linked to a dynamical transition in the order parameter.