# The Dicke model phase transition in the quantum motion of a Bose-Einstein condensate in an optical cavity

## TL;DR

This paper demonstrates that the quantum motion of a laser-driven Bose-Einstein condensate in an optical cavity can realize the Dicke model, showing a phase transition from normal to superradiant states linked to atomic self-organization.

## Contribution

It establishes a physical realization of the Dicke model using Bose-Einstein condensates in optical cavities and analyzes the associated quantum phase transition and ground state fragility.

## Key findings

- Observation of the Dicke-model phase transition in BEC motion
- Identification of self-organization as the superradiant phase
- Calculation of ground state fragility due to photon measurement back action

## Abstract

We show that the motion of a laser-driven Bose-Einstein condensate in a high-finesse optical cavity realizes the spin-boson Dicke-model. The quantum phase transition of the Dicke-model from the normal to the superradiant phase corresponds to the self-organization of atoms from the homogeneous into a periodically patterned distribution above a critical driving strength. The fragility of the ground state due to photon measurement induced back action is calculated.