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  • Open Access

Metastability, chaos, and spectrum tomography for Bose-Hubbard rings and chains

Rajat* and Doron Cohen†

  • *Contact author: rajat@post.bgu.ac.il
  • †Contact author: dcohen@bgu.ac.il
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Phys. Rev. Research 8, 033024 – Published 6 July, 2026

DOI: https://doi.org/10.1103/dbpg-938z

Abstract

We analyze the metastability of Bose-Hubbard condensates for finite-size one-dimensional ring lattices and open chains, using a semiclassical tomographic perspective that emphasizes the relation of the many-body spectrum to the underlying classical phase-space structures. In order to address quantum ergodicity in far-from-equilibrium scenarios of experimental interest, we inspect both local aspects (via Bogoliubov analysis) and global aspects (mixed regular-chaotic dynamics). In particular, we highlight the roles of the two parameters that control metastability, clarify the essential differences between low- and high-dimensional chaos, and show how the dynamical instabilities diminish in the limit of the Gross-Pitaevskii equation. It is somewhat frustrating that with more degrees of freedom, the dynamically metastable islands become better distinct from the ergodic sea, while their borders become ill-defined topologically. This stands in opposition to the very structured phase space of two-degree-of-freedom systems, as reflected in the tomographic quantum spectrum.

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Phys. Rev. Research 8, 033024– Published 6 July, 2026
  • Received 24 March 2026
  • Accepted 18 June 2026
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