Probing microscopic models for system-bath interactions via parametric driving

TL;DR

This paper demonstrates that strong parametric driving of a quantum harmonic oscillator coupled to a thermal bath can differentiate between microscopic models of system-bath interactions by analyzing the dependence of position and momentum variances on driving parameters.

Contribution

It introduces a method to distinguish microscopic system-bath coupling models using parametric driving and analyzes the resulting steady-state variances.

Findings

Variance depends strongly on driving parameters and coupling angle.

Identifies regimes maximizing the dependence on the coupling angle.

Provides an intuitive explanation for the observed dependence.

Abstract

We show that strong parametric driving of a quantum harmonic oscillator coupled to a thermal bath allows one to distinguish between different microscopic models for the oscillator-bath coupling. We consider a bath with an Ohmic spectral density and a model where the system-bath interaction can be tuned continuously between position and momentum coupling via the coupling angle $\alpha$. We derive a master equation for the reduced density operator of the oscillator in Born-Markov approximation and investigate its quasi-steady state as a function of the driving parameters, the temperature of the bath and the coupling angle $\alpha$. We find that the time-averaged variance of position and momentum exhibits a strong dependence on these parameters. In particular, we identify parameter regimes that maximise the $\alpha$-dependence and provide an intuitive explanation of our results.