Two-Polariton Blockade via Ultrastrong Light-Matter Coupling

TL;DR

This paper demonstrates the occurrence of two-polariton blockade in an atom-cavity system operating in the ultrastrong coupling regime, revealing a new quantum light source mechanism distinct from previous regimes.

Contribution

It introduces a novel method to achieve two-polariton blockade in the ultrastrong coupling regime using modified correlation functions, unattainable in strong or weak coupling regimes.

Findings

Two-polariton blockade occurs under resonant single-polariton driving in USC regime.

Pronounced two-polariton bunching observed with suppressed three-polariton coincidences.

Potential for new multiparticle quantum light sources in the USC regime.

Abstract

We demonstrate that a two-polariton blockade (2PB) can occur under resonant single-polariton driving in an atom-cavity system operating in the ultrastrong coupling (USC) regime-a phenomenon qualitatively distinct from, and unattainable in, both the strong and weak coupling regimes. In the USC regime, where the ratio of the atom-cavity coupling strength to the cavity resonance frequency exceeds 0.1, hybrid light-matter quasiparticles known as polaritons emerge. By employing modified second- and third-order correlation functions appropriate for the USC regime, we predict the emergence of 2PB, characterized by pronounced two-polariton bunching accompanied by suppressed three-polariton coincidences. This Letter introduces a novel route to achieving 2PB, with promising implications for the realization of multiparticle quantum light sources in the USC regime.