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arXiv · 2504.18426

PT-symmetry breaking phase transitions in an LMG dimer

Simon Kothe·Christopher Oliver·Peter Kirton
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Abstract

The open Lipkin-Meshkov-Glick (LMG) model provides a prototype of a dissipative phase transition which can be analyzed using mean-field theory. By combining the physics of this model with those of a quantum analogue of a parity-time reversal symmetry breaking transition we analyze the steady state phase diagram of a pair of coupled LMG models. Their competition generates a complex phase diagram with multiple steady-state phases and emergent dynamical regimes absent from either constituent model, including chaos characterized by the maximum Lyapunov exponent. We show that the effects predicted from mean-field theory survive in the full quantum model.

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Simon Kothe, Christopher Oliver, Peter Kirton. 2026-07-06. PT-symmetry breaking phase transitions in an LMG dimer. https://arxiv.org/abs/2504.18426

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