Regensburg 2010 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 31: Statistical Physics far from Equilibrium

DY 31.1: Topical Talk

Freitag, 26. März 2010, 10:15–10:45, H38

Real-time transport and dynamics in strongly interacting one-dimensional systems — •Fabian Heidrich-Meisner — LMU Munich, Germany

The question of ballistic and diffusive dynamics in one-dimensional systems has a long history, both for classical and quantum systems. In the quantum case, there exist several examples such as heat transport in Heisenberg chains where integrability renders transport anomalous giving rise to ballistic behavior even at finite temperatures. While most studies have focussed on the linear response regime [1], in this talk, I will address similar questions for systems driven out of equilibrium. Using the time-dependent DMRG technique, a particular set-up is used, namely the expansion of wave-packets in either a zero [2] or finite background density [3]. The former is relevant for transport experiments on bulk materials such as low-dimensional quantum magnets whereas the latter can be directly studied with ultracold atoms in optical lattices. I will argue that this set-up allows us to identify ballistic and diffusive time regimes, depending on model parameters and initial conditions [3]. The models under scrutiny comprise spin chains and the 1D Hubbard model as well as perturbations around these two integrable limits. I shall further emphasize emergent non-equilibrium phenomena and discuss the behavior of the entanglement entropy [2].

[1] Heidrich-Meisner et al., EPJ Spec. Topics 151, 135 (2007)

[2] Heidrich-Meisner et al., Phys. Rev. A 80, 041603(R) (2009)

[3] Langer et al., Phys. Rev. B 79, 214409 (2009)