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Eigenstate thermalization to nonmonotonic distributions in strongly interacting chaotic lattice gases

Vladimir A. Yurovsky*

Amichay Vardi†

  • *Contact author: volodia@post.tau.ac.il
  • †Contact author: avardi@bgu.ac.il
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Phys. Rev. Research 7, 043354 – Published 31 December, 2025

DOI: https://doi.org/10.1103/4cq3-nfb2

Abstract

We find nonmonotonic equilibrium energy distributions, qualitatively different from the Fermi-Dirac and Bose-Einstein forms, in strongly interacting many-body chaotic systems. The effect emerges in systems with finite energy spectra, supporting both positive and negative temperatures, in the regime of quantum ergodicity. The results are supported by exact diagonalization calculations for chaotic Fermi-Hubbard and Bose-Hubbard models, when they have Wigner-Dyson statistics of energy spectra and demonstrate eigenstate thermalization. The proposed effects may be observed in experiments with cold atoms in optical lattices.

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Phys. Rev. Research 7, 043354– Published 31 December, 2025
  • Received 3 January 2025
  • Revised 1 April 2025
  • Accepted 17 December 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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