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arXiv · 1812.07981

Logarithmic spreading of out-of-time-ordered correlators without many-body localization

Adam Smith·Johannes Knolle·Roderich Moessner·Dmitry L. Kovrizhin
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Abstract

Out-of-time-ordered correlators (OTOCs) describe information scrambling under unitary time evolution, and provide a useful probe of the emergence of quantum chaos. Here we calculate OTOCs for a model of disorder-free localization whose exact solubility allows us to study long-time behaviour in large systems. Remarkably, we observe logarithmic spreading of correlations, qualitatively different to both thermalizing and Anderson localized systems. Rather, such behaviour is normally taken as a signature of many-body localization, so that our findings for an essentially non-interacting model are surprising. We provide an explanation for this unusual behaviour, and suggest a novel Loschmidt echo protocol as a probe of correlation spreading. We show that the logarithmic spreading of correlations probed by this protocol is a generic feature of localized systems, with or without interactions.

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Adam Smith, Johannes Knolle, Roderich Moessner, Dmitry L. Kovrizhin. 2018-12-19. Logarithmic spreading of out-of-time-ordered correlators without many-body localization. https://doi.org/10.1103/physrevlett.123.086602

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