Dresden 2017 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 10: Transport: Topological Phases (jointly with DS/MA/TT)
DS 10.1: Vortrag
Montag, 20. März 2017, 15:00–15:15, HSZ 304
Dynamical Buildup of a Quantized Hall Response from Non-Topological States — Ying Hu1, Peter Zoller1,2, and •Jan Carl Budich3 — 1Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, 6020 Innsbruck, Austria — 2Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria — 3Department of Physics, University of Gothenburg, SE 412 96 Gothenburg, Sweden
We consider a two-dimensional system initialized in a topologically trivial state before its Hamiltonian is ramped through a phase transition into a Chern insulator regime. This scenario is motivated by current experiments with ultracold atomic gases aimed at realizing time-dependent dynamics in topological insulators. Our main findings are twofold. First, considering coherent dynamics, the non-equilibrium Hall response is found to approach a topologically quantized time averaged value in the limit of slow but non-adiabatic parameter ramps, even though the Chern number of the state remains trivial. Second, adding dephasing, the destruction of quantum coherence is found to stabilize this Hall response, while the Chern number generically becomes undefined. We provide a geometric picture of this phenomenology in terms of the time-dependent Berry curvature.