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arXiv · 1201.2844

Coexistence of Anomalous and Normal Diffusion in Integrable Mott Insulators

R. Steinigeweg·J. Herbrych·P. Prelovšek·M. Mierzejewski
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Abstract

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.

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R. Steinigeweg, J. Herbrych, P. Prelovšek, M. Mierzejewski. 2012-01-13. Coexistence of Anomalous and Normal Diffusion in Integrable Mott Insulators. https://doi.org/10.1103/physrevb.85.214409

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