Large and small fluctuations in oscillator networks from heterogeneous and correlated noise

TL;DR

This paper investigates how heterogeneous and correlated noise influence fluctuations in oscillator networks, particularly Kuramoto models, by analyzing small and large fluctuations and introducing an approximation to estimate phase slip rates.

Contribution

It introduces the indicator mode approximation to estimate large fluctuation rates and connects network variance to noise covariance, advancing understanding of noise effects in oscillator networks.

Findings

Small fluctuations are linked to stable mode overlaps and noise covariance.

Large fluctuation rates can be estimated using the indicator mode approximation.

Higher network variance does not always mean higher large fluctuation rates.

Abstract

Oscillatory networks subjected to noise are broadly used to model physical and technological systems. Due to their nonlinear coupling, such networks typically have multiple stable and unstable states that a network might visit due to noise. In this manuscript, we focus on the assessment of fluctuations resulting from heterogeneous and correlated noise inputs on Kuramoto model networks. We evaluate the typical, small fluctuations near synchronized states and connect the network variance to the overlap between stable modes of synchronization and the input noise covariance. Going beyond small to large fluctuations, we introduce the indicator mode approximation, that projects the dynamics onto a single amplitude dimension. Such an approximation allows for estimating rates of fluctuations to saddle instabilities, resulting in phase slips between connected oscillators. Statistics for both regimes are quantified in terms of effective noise amplitudes that are compared and contrasted for several noise models. Bridging the gap between small and large fluctuations, we show that a larger network variance does not necessarily lead to higher rates of large fluctuations.