Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 73: Correlated Electrons: Nonequilibrium Quantum Many-Body Systems 2
TT 73.9: Vortrag
Donnerstag, 23. März 2017, 17:15–17:30, HSZ 304
Real-time broadening of non-equilibrium density profiles and the role of the specific initial-state realization — •Robin Steinigeweg1, Fengping Jin2, Daniel Schmidtke1, Hans De Raedt3, Kristel Michielsen2,4, and Jochen Gemmer1 — 1University Osnabrück — 2Forschungszentrum Jülich — 3University Groningen — 4RWTH Aachen University
The real-time broadening of density profiles starting from non-equilibrium states is at the center of transport in condensed-matter systems and dynamics in ultracold atomic gases. Initial profiles close to equilibrium are expected to evolve according to linear response, e.g., as given by the current correlator evaluated exactly at equilibrium. Significantly off equilibrium, linear response is expected to break down and even a description in terms of canonical ensembles is questionable. We unveil [1] that single pure states with density profiles of maximum amplitude yield a broadening in perfect agreement with linear response, if the structure of these states involves randomness in terms of decoherent off-diagonal density-matrix elements. While these states allow for spin diffusion in the XXZ spin-1/2 chain at large exchange anisotropies, coherences yield entirely different behavior.
[1] R. Steinigeweg et al., arXiv:1610.05778 (2016).