Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 40: Poster Session Correlated Electrons
TT 40.56: Poster
Mittwoch, 13. März 2013, 15:00–19:00, Poster D
Coexistence of anomalous and normal diffusion in integrable Mott insulators — •Robin Steinigeweg1,2, Jacek Herbrych2, Peter Prelovšek2, and Marcin Mierzejewski3 — 1Institute for Theoretical Physics, Technical University Braunschweig, D-38106 Braunschweig — 2Department of Theoretical Physics, Jožef Stefan Institute, SI-1000 Ljubljana — 3Institute of Physics, University of Silesia, PL-40-007 Katowice
We study the finite-momentum spin dynamics in the one-dimensional XXZ spin chain within the Ising-type regime at high temperatures using density autocorrelations within linear response theory and real-time propagation of nonequilibrium densities. While for the nonintegrable model results are well consistent with normal diffusion, the finite-size integrable model unveils the coexistence of anomalous and normal diffusion in different regimes of time. In particular, numerical results show a Gaussian relaxation at smallest nonzero momenta which we relate to nonzero stiffness in a grand canonical ensemble. For larger but still small momenta normal-like diffusion is recovered. Similar results for the model of impenetrable particles also help to resolve rather conflicting conclusions on transport in integrable Mott insulators.