Diffusive transport in a quasiperiodic Fibonacci chain: Absence of many-body localization at weak interactions Article Swipe
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· 2019
· Open Access
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· DOI: https://doi.org/10.1103/physrevb.100.085105
· OA: W2944718329
We study high-temperature magnetization transport in a many-body spin-1/2\nchain with on-site quasiperiodic potential governed by the Fibonacci rule. In\nthe absence of interactions it is known that the system is critical with the\ntransport described by a continuously varying dynamical exponent (from\nballistic to localized) as a function of the on-site potential strength. Upon\nintroducing weak interactions, we find that an anomalous noninteracting\ndynamical exponent becomes diffusive for any potential strength. This is borne\nout by a boundary-driven Lindblad dynamics as well as unitary dynamics, with\nagreeing diffusion constants. This must be contrasted to random potential where\ntransport is subdiffusive at such small interactions. Mean-field treatment of\nthe dynamics for small U always slows down the non-interacting dynamics to\nsubdiffusion, and is therefore unable to describe diffusion in an interacting\nquasiperiodic system. Finally, briefly exploring larger interactions we find a\nregime of interaction-induced subdiffusive dynamics, despite the on-site\npotential itself having no "rare-regions".\n
