Quantum heating of a parametrically modulated oscillator: spectral signatures

TL;DR

This paper investigates how quantum heating affects the noise spectrum of a parametrically modulated nonlinear oscillator, revealing a fine spectral structure that serves as a sensitive probe of the quasienergy distribution.

Contribution

It demonstrates that quantum heating causes a finite-width quasienergy distribution and introduces a fine spectral structure, providing new insights into quantum noise in driven nonlinear systems.

Findings

Spectral fine structure arises from quasienergy level transitions.

Quantum heating results in a finite quasienergy distribution at zero temperature.

Double-peak spectral features indicate quantum heating effects at larger damping.

Abstract

We show that the noise spectrum of a parametrically excited nonlinear oscillator can display a fine structure. It emerges from the interplay of the nonequidistance of the oscillator quasienergy levels and quantum heating that accompanies relaxation. The heating leads to a finite-width distribution over the quasienergy, or Floquet states even for zero temperature of the thermal reservoir coupled to the oscillator. The fine structure is due to transitions from different quasienergy levels, and thus it provides a sensitive tool for studying the distribution. For larger damping, where the fine structure is smeared out, quantum heating can be detected from the characteristic double-peak structure of the spectrum, which results from transitions accompanied by the increase or decrease of the quasienergy.