Quantum phase transitions and entanglement entropy in a non-Hermitian Jaynes-Cummings model
Abstract
In this paper, we describe some interesting properties of a non-Hermitian Jaynes-Cummings model. For this particular model, it is known that the Hilbert space can be described by infinitely-many two-dimensional invariant (closed) subspaces, together with the global ground state. We expose the appearance of exceptional points on such two-dimensional subspaces, together with quantum phase transitions marking the transition from real to complex eigenvalues. We also compute the spin-oscillator entanglement entropy on each invariant subspace to show that the two phases can be distinguished by their distinct entanglement-entropy profiles.
Keywords
Cite
@article{arxiv.2506.23356,
title = {Quantum phase transitions and entanglement entropy in a non-Hermitian Jaynes-Cummings model},
author = {Gargi Das and Aritra Ghosh and Bhabani Prasad Mandal},
journal= {arXiv preprint arXiv:2506.23356},
year = {2026}
}
Comments
v1: 9 pages, 5 figures; v2: 18 pages, 3 figures, several errors corrected and substantially revised; v3: Published in Annals of Physics; the arXiv version also includes a clarifying footnote added post-publication, along with two minor edits to Sec. 5