Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: Poster Session: Correlated Electrons 1

TT 19.62: Poster

Montag, 20. März 2017, 15:00–19:00, P2-EG

Pumping approximately integrable systems — •Florian Lange, Zala Lenarcic, and Achim Rosch — Universität zu Köln

Weak perturbations can drive an interacting many-particle system far from its initial equilibrium state if one is able to pump into degrees of freedom approximately protected by conservation laws. This concept has for example been used to realize Bose-Einstein condensates of photons, magnons, and excitons. Integrable quantum systems like the one-dimensional Heisenberg model are charac- terized by an infnite set of conservation laws. Here we develop a theory of weakly driven integrable systems and show that pumping can induce huge spin or heat currents even in the presence of integrability breaking perturbations, since it activates local and quasi-local approximate conserved quantities. The resulting steady state is qualitatively captured by a (truncated) generalized Gibbs ensemble with Lagrange parameters that depend on the structure but not on the overall ampli- tude of perturbations or on the initial state. We suggest to realize novel heat or spin pumps using spin-chain materials driven by THz radiation.