Cavity QED simulation of qubit-oscillator dynamics in the ultrastrong coupling regime

TL;DR

This paper proposes a quantum simulation method for ultrastrong coupling in cavity QED using resonant Raman transitions in rubidium atoms, enabling exploration of nonlinear and critical phenomena at the single-atom level.

Contribution

It introduces a novel scheme for simulating ultrastrong atom-cavity interactions with realistic parameters and accounts for dissipation effects.

Findings

Numerical simulations show feasibility with rubidium atoms and microtoroidal resonators.

The system can simulate nonlinear coupling and critical behavior.

Observable outputs are identified for experimental detection.

Abstract

We propose a quantum simulation of a two-level atom coupled to a single mode of the electromagnetic field in the ultrastrong-coupling regime based upon resonant Raman transitions in an atom interacting with a high finesse optical cavity mode. We show by numerical simulation the possibility of realizing the scheme with a single rubidium atom, in which two hyperfine ground states make up the effective two-level system, and for cavity QED parameters that should be achievable with, for example, microtoroidal whispering-gallery-mode resonators. Our system also enables simulation of a generalized model in which a nonlinear coupling between the atomic inversion and the cavity photon number occurs on an equal footing with the (ultrastrong) dipole coupling and can give rise to critical-type behavior even at the single-atom level. Our model takes account of dissipation, and we pay particular attention to observables that would be readily observable in the output from the system.