Bell-inequality violation in light transmitted through disordered emitter ensembles

Abstract:We show that light transmitted through a disordered ensemble of weakly coupled two-level emitters can violate a Bell inequality in a continuous-wave Franson-type measurement. The Bell signal is determined by two steady-state output-field correlations, the equal-time intensity correlation $g^{(2)}(0)$ and the phase-sensitive two-photon coherence $R$. We compute these quantities for bidirectional propagation through disordered emitter ensembles using a fourth-order cumulant expansion of the many-body master equation. The resulting Bell inequality violation appears in two distinct regimes, an antibunched regime where equal-time coincidences are suppressed and a bunched regime where photon pairs remain phase coherent. Extrapolating the numerics to a representative weak single-emitter coupling $\beta=0.01$ predicts violation in the antibunched regime for atom numbers $N\simeq75$-$220$, and in the bunched regime for $N\gtrsim250$.

Quantum Physics (quant-ph); Optics (physics.optics)

arXiv:2609.15575 [quant-ph]

(or arXiv:2609.15575v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2609.15575 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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