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arXiv · 2609.37512

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

Taiki Ishiyama·Taiga Kurose·Kazuya Fujimoto·Tomohiro Sasamoto
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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.

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Taiki Ishiyama, Taiga Kurose, Kazuya Fujimoto, Tomohiro Sasamoto. 2026-09-29. Exact anomalous current fluctuations in the strong-anisotropy limit of the XXZ chain. https://arxiv.org/abs/2609.37512

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