Supernarrow spectral peaks near a kinetic phase transition in a driven, nonlinear micromechanical oscillator

TL;DR

This study investigates a nonlinear micromechanical oscillator exhibiting a kinetic phase transition, where noise-induced switching causes supernarrow spectral peaks near a critical frequency, revealing parallels to thermal phase transitions.

Contribution

It demonstrates the observation of supernarrow spectral peaks associated with a kinetic phase transition in a driven nonlinear oscillator, linking nonequilibrium dynamics to phase transition phenomena.

Findings

Supernarrow spectral peaks occur at the transition frequency.

Noise-induced switching between dynamical states causes these peaks.

The system exhibits a phase transition-like behavior in a driven oscillator.

Abstract

We measure the spectral densities of fluctuations of an underdamped nonlinear micromechanical oscillator. By applying a sufficiently large periodic excitation, two stable dynamical states are obtained within a particular range of driving frequency. White noise is injected into the excitation, allowing the system to overcome the activation barrier and switch between the two states. While the oscillator predominately resides in one of the two states for most excitation frequencies, a narrow range of frequencies exist where the occupations of the two states are approximately equal. At these frequencies, the oscillator undergoes a kinetic phase transition that resembles the phase transition of thermal equilibrium systems. We observe a supernarrow peak in the power spectral densities of fluctuations of the oscillator. This peak is centered at the excitation frequency and arises as a result of noise-induced transitions between the two dynamical states.