# The quantum Rabi model in a superfluid Bose-Einstein condensate

## TL;DR

This paper proposes a highly tunable quantum simulation platform using a single atom in a superfluid Bose-Einstein condensate to explore the quantum Rabi model and its transition to the ultrastrong coupling regime.

## Contribution

It introduces a novel cold-atom setup for simulating the quantum Rabi model, including the transition to ultrastrong coupling and multi-qubit interactions.

## Key findings

- Simulation of the quantum Rabi model in a cold-atom system.
- Potential to explore ultrastrong coupling regime.
- Extension to multi-qubit interactions via phononic exchange.

## Abstract

We propose a quantum simulation of the quantum Rabi model in an atomic quantum dot, which is a single atom in a tight optical trap coupled to the quasiparticle modes of a superfluid Bose-Einstein condensate. This widely tunable setup allows to simulate the ultrastrong coupling regime of light-matter interaction in a system which enjoys an amenable characteristic timescale, paving the way for an experimental analysis of the transition between the Jaynes-Cummings and the quantum Rabi dynamics using cold-atom systems. Our scheme can be naturally extended to simulate multi-qubit quantum Rabi models. In particular, we discuss the appearance of effective two-qubit interactions due to phononic exchange, among other features.