Interaction-Enhanced Superradiance of a Ryderg-Atom Array

TL;DR

This paper investigates how long-range Rydberg interactions in an array within a dissipative microwave cavity lead to an interaction-enhanced superradiant phase transition, with critical points characterized by emergent quantum Rabi models.

Contribution

It reveals the phenomenon of interaction-enhanced superradiance in Rydberg atom arrays and analyzes its persistence under realistic spatially dependent interactions.

Findings

Superradiant phase transition occurs at vanishing atom-cavity coupling at discrete interaction strengths.

Emergent quantum Rabi models describe the critical points with degenerate collective states.

Enhanced superradiance persists under experimental conditions with spatially varying interactions.

Abstract

We study the superradiant phase transition of an array of Rydberg atoms in a dissipative microwave cavity. Under the interplay of the cavity field and the long-range Rydberg interaction, the steady state of the system exhibits an interaction-enhanced superradiance, with vanishing critical atom-cavity coupling rates at a discrete set of interaction strengths. We find that, while the phenomenon can be analytically understood in the case of a constant all-to-all interaction, the enhanced superradiance persists under typical experimental parameters with spatially dependent interactions, but at modified critical interaction strengths. The diverging susceptibility at these critical points is captured by emergent quantum Rabi models, each of which comprises a pair of collective atomic states with different numbers of atomic excitations. These collective states become degenerate at the critical interaction strengths, resulting in a superradiant phase for an arbitrarily small atom-cavity coupling.