Detection of emitter-resonator coupling strength in quantum Rabi model via an auxiliary resonator

TL;DR

This paper proposes a theoretical method to measure the emitter-resonator coupling strength in the ultra-strong regime of the quantum Rabi model by using an auxiliary resonator to enhance detection sensitivity.

Contribution

It introduces a novel scheme employing an auxiliary resonator and a transformed rotating wave approximation to accurately detect coupling strength in the quantum Rabi model.

Findings

The auxiliary resonator improves detection sensitivity.

The transformed RWA provides a better approximation than the usual RWA.

The scheme enables precise measurement of coupling strength.

Abstract

In this paper, we propose a theoretical scheme to detect the emitter-resonator coupling strength in the ultra-strong coupling regime in the quantum Rabi model via introducing an auxiliary resonator. We demonstrate the total system as a two-mode Rabi model and obtain the ground state by the transformed rotating wave approximation, which is shown to be superior to the usually applied rotating wave approximation. Here, the coupling strength is detected by monitoring the average excitation number in the auxiliary resonator and the sensitivity of the detection scheme is discussed analytically.