Exact anomalous current fluctuations in the strong-anisotropy limit of the XXZ chain

Abstract:We study spin-current fluctuations of the folded XXZ chain, which describes the strong-anisotropy limit of the XXZ chain. We obtain an exact expression for the moment-generating function of the time-integrated spin current at infinite temperature. A long-time asymptotic analysis establishes that the rescaled time-integrated current converges to a non-Gaussian distribution described by the M-Wright function. The derivation relies on a nonlocal map to the one-dimensional t-0 model and its exact spin-charge separation. By extending this approach, we also show that the dynamical correlation function of the spins summed over two adjacent sites exhibits a diffusive Gaussian profile at long times.

Statistical Mechanics (cond-mat.stat-mech); Quantum Gases (cond-mat.quant-gas); Mathematical Physics (math-ph); Quantum Physics (quant-ph)

arXiv:2609.37512 [cond-mat.stat-mech]

(or arXiv:2609.37512v1 [cond-mat.stat-mech] for this version)

https://doi.org/10.48550/arXiv.2609.37512 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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