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arXiv · 2506.23356

Quantum phase transitions and entanglement entropy in a non-Hermitian Jaynes-Cummings model

Gargi Das·Aritra Ghosh·Bhabani Prasad Mandal
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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.

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Gargi Das, Aritra Ghosh, Bhabani Prasad Mandal. 2025-06-29. Quantum phase transitions and entanglement entropy in a non-Hermitian Jaynes-Cummings model. https://doi.org/10.1016/j.aop.2026.170484

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