Quantum fluctuations in modulated nonlinear oscillators

TL;DR

This paper investigates quantum fluctuations in modulated nonlinear oscillators, revealing phenomena like quantum heating, rare large fluctuations, and switching dynamics, with implications for understanding quantum behavior far from thermal equilibrium.

Contribution

It introduces analysis of quantum heating, rare fluctuation paths, and nonresonant field effects in modulated oscillators, advancing understanding of quantum dynamics in nonequilibrium systems.

Findings

Quantum heating causes a finite-width quasienergy distribution.

Most probable paths characterize rare fluctuation events.

Discontinuous switching paths occur when detailed balance breaks.

Abstract

With a modulated oscillator, we study several effects of quantum fluctuations far from thermal equilibrium. One of them is quantum heating, where quantum fluctuations lead to a finite-width distribution of a resonantly modulated oscillator over its quasienergy (Floquet) states. We also analyze large rare fluctuations responsible for the tail of the quasienergy distribution and switching between the states of forced vibrations. We find an observable characteristic of these fluctuations, the most probable paths followed by the quasienergy in rare events, and in particular in switching. We also explore the discontinuous change of the most probable switching path where the detailed balance condition is broken. For oscillators modulated by a nonresonant field, we compare different mechanisms of the field-induced cooling and heating of the oscillator.