Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 53: Quantum Gases: Fermions I
Q 53.7: Vortrag
Donnerstag, 3. März 2016, 16:00–16:15, e001
Quench Dynamics in Spin Chains from Discrete Truncated Wigner Approximations — •Stefanie Czischek1, Halil Cakir1, Markus Karl1, Michael Kastner2, Markus K. Oberthaler1, and Thomas Gasenzer1 — 1Kirchhoff-Institut für Physik, INF 227, 69120 Heidelberg, Germany — 2Institute of Theoretical Physics, University of Stellenbosch, Stellenbosch 7600, South Africa
We study the dynamical build-up of correlations after sudden quenches in spin chains using the novel discrete truncated Wigner approximation. In particular, we consider quenches from large external fields to the vicinity of the quantum critical point within the paramagnetic phase. We calculate correlation lengths and regard their time evolution at different distances from the critical point. For the transverse field Ising chain, we find that the discrete truncated Wigner approximation is in good agreement with exact analytical and numerical results. Furthermore, our results show that the correlation function takes the form given by a generalized Gibbs ensemble already after short times and small relative distances. Since the generalized Gibbs ensemble usually describes the behaviour for asymptotically large times and distances, this is in contrast to expectations. Thus, our results suggests that the effects of universal dynamics are accessible on experimentally realizable timescales.