Heidelberg 2015 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 27: Quantum Gases: Bosons IV
Q 27.3: Talk
Tuesday, March 24, 2015, 15:00–15:15, P/H2
Scaling behaviour in quantum quench dynamics — •Markus Karl1,2, Aisling Johnson2, Eike Nicklas2, Markus Oberthaler2, and Thomas Gasenzer1,2 — 1Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg — 2Kirchhoff-Institute for Physics, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg
We present results on scaling features which appear during the dynamical evolution of a quantum system as a consequence of a rapid parameter quench near a phase transition. We focus on a binary mixture of Rubidium-87 hyperfine states, in one spatial dimension, where the relative degrees of freedom can be mapped onto a system of collective spins. The strength of a Rabi coupling between the two hyperfine states controls a Ising-class quantum phase transition within the spin system. Here, we study quench dynamics by means of classical-statistical simulations and compare our results to Bogoliubov theory for the spin system and recent experimental data. Quenching the Rabi coupling to the vicinity of the quantum critical point, scale invariance of the spatial and temporal behaviour is observed, both theoretically and experimentally. Our data indicates that even far from thermal equilibrium universal behaviour corresponding to a stationary system can be identified. The theoretical findings suggest that close to the critical point of the spin system the energy introduced by the quench leads to a crossover behaviour reminiscent of the finite-temperature critical properties the Ising-class system.