Dissipative phase transitions of the Dicke-Ising model

TL;DR

This paper explores how dissipation affects phase transitions in the Dicke-Ising model, revealing new bistable states and phase behaviors in open quantum systems through mean-field and stability analyses.

Contribution

It introduces a detailed analysis of dissipative phase transitions in the Dicke-Ising model, highlighting the stabilization of bistable states and the emergence of first-order transitions absent in the ground state.

Findings

Dissipation slightly shifts the phase diagram of the transverse DIM.

Longitudinal DIM dissipation stabilizes bistable nonequilibrium states.

Identification of a tetracritical point where multiple phase boundaries meet.

Abstract

The dissipative phase transitions in the open transverse and longitudinal Dicke-Ising model (DIM), which incorporates nearest-neighbor Ising-type spin interactions into the Dicke framework, are investigated within a mean-field approach and further validated by detailed stability analysis. While the dissipative phase diagram of the transverse DIM is only slightly shifted upward compared with its ground-state counterpart, dissipation in the longitudinal DIM stabilizes bistable nonequilibrium steady states and induces first-order phase transitions that are absent in the ground-state phase diagram. This bistable phase is characterized by the coexistence of superradiant and antiferromagnetic orders, and it converts a ground-state triple point into a tetracritical point, at which the boundaries of the first- and second-order transitions intersect. Our results reveal that the interplay among spin interactions, light-matter coupling, and dissipation supports a diverse set of nonequilibrium phase transitions and provides broad tunability of the phase diagram. These findings offer a theoretical foundation for exploring nonequilibrium physics in realistic open solid-state quantum systems.