Fragmented Superradiance of a Bose-Einstein Condensate in an Optical Cavity

TL;DR

This paper investigates the phenomenon of fragmented superradiance in a Bose-Einstein condensate within an optical cavity, revealing a new phase where multiple modes are macroscopically occupied while maintaining superradiance.

Contribution

It introduces the concept of fragmented superradiance in a BEC-cavity system and demonstrates this phase through numerical solutions of the many-body Schrödinger equation.

Findings

Identification of a critical driving strength for fragmentation

Observation of multiple mode occupation in the superradiant phase

Detection method via variance analysis of measurements

Abstract

The Dicke model and the superradiance of two-level systems in a radiation field have many applications. Recently, a Dicke quantum phase transition has been realized with a Bose-Einstein condensate in a cavity. We numerically solve the many-body Schr\"odinger equation and study correlations in the ground state of interacting bosons in a cavity as a function of the strength of a driving laser. Beyond a critical strength, the bosons occupy multiple modes macroscopically while remaining superradiant. This fragmented superradiance can be detected by analyzing the variance of single-shot measurements.