Generic shape of multichromatic resonance peaks

TL;DR

This paper explores universal features of multichromatic resonance peaks in dissipative systems, revealing how long-time averages exhibit a universal envelope and phase dependence changes with averaging time, supported by classical and quantum examples.

Contribution

It analytically derives the universal envelope of resonance peaks and illustrates the transition of phase dependence from short to long times in dissipative systems with biharmonic driving.

Findings

Resonance peaks have a universal envelope inversely proportional to averaging time.

Phase dependence transitions from 2π periodicity to a fractional period over time.

Long-time averages exhibit universal features derived analytically.

Abstract

We investigate dissipative dynamical systems under the influence of an external driving with two or more frequencies. Our main quantities of interest are long-time averages of expectation values which turn out to exhibit universal features. In particular, resonance peaks in the vicinity of commensurable frequencies possess a generic enveloping function whose width is inversely proportional to the averaging time. While the universal features can be derived analytically, the transition from the specific short-time behavior to the long-time limit is illustrated for the examples of a classical random walk and a dissipative two-level system both with biharmonic driving. In these models, the dependence of the time-averaged response on the relative phase between the two driving frequencies changes with increasing integration time. For short times, it exhibits the $2\pi$ periodicity of the dynamic equations, while in the long-time limit, the period becomes a fraction of this value.