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arXiv · 2607.20688

Bistability of Exciton-Photon Microcavities in the Ultrastrong-Coupling Regime

Rashed Aljasmi·Hisham Sati·Hichem Eleuch
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Abstract

We investigate a coherently driven exciton--photon microcavity with Kerr nonlinearity in the ultrastrong-coupling regime. When the lower and upper polariton branches are well separated in energy, the full Hopfield--Rabi--Kerr model reduces to an effective single-mode description of the lower polariton. We analyze the stability of the lower-polariton steady states. We show that the resulting bistability is qualitatively similar to that in the strong-coupling regime. However, in the ultrastrong-coupling regime counter-rotating processes and the diamagnetic $A^{2}$ term renormalize the polariton spectrum and composition, changing the effective detuning $\tilde{\Delta}_{1}$ and nonlinearity $U_{\mathrm{LP}}$ $g$-dependency beyond the strong-coupling (RWA) picture. As a result, although the semiclassical bistability criterion keeps its standard Kerr--oscillator form, the turning points and hysteresis window are shifted relative to the strong-coupling prediction.

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Rashed Aljasmi, Hisham Sati, Hichem Eleuch. 2026-07-22. Bistability of Exciton-Photon Microcavities in the Ultrastrong-Coupling Regime. https://doi.org/10.1016/j.chaos.2026.118218

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