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  • Open Access

Quantum thermalization and the route to ergodicity

Amichay Vardi1,2,* and Doron Cohen3,†

  • *Contact author: avardi@bgu.ac.il
  • †Contact author: dcohen@bgu.ac.il
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Phys. Rev. Research 7, 043293 – Published 15 December, 2025

DOI: https://doi.org/10.1103/7355-1nlj

Abstract

We consider a minimal model for quantum thermalization of coupled chaotic subsystems. The route toward ergodicity is explored as a function of the coupling strength. The results are contrasted with the predictions of standard random matrix theory and the eigenstates thermalization hypothesis. We highlight a coupling regime of disparity between the spectral statistics that indicates chaos and ergodicity measures that indicate lack of eigenstate thermalization. The analysis involves a revision of the energy-shell concept, in a way that is consistent but independent of the semiclassical perspective.

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Corrections

26 January, 2026

Correction: A misprint in the heading for Sec. V has been fixed.

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Phys. Rev. Research 7, 043293– Published 15 December, 2025
  • Received 29 July 2025
  • Accepted 14 November 2025
  • Corrected 26 January 2026
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