Synchronization by noise for traveling pulses

TL;DR

This paper demonstrates that noise can synchronize traveling pulse solutions in stochastic PDEs like the FitzHugh-Nagumo model, with convergence occurring over a specific time scale, using phase reduction techniques.

Contribution

It introduces a phase reduction method to prove noise-induced synchronization of traveling pulses in stochastic PDEs, extending understanding of stochastic effects on wave solutions.

Findings

Pulse solutions converge in probability under common noise

Synchronization occurs on a time scale proportional to the inverse square of noise amplitude

Phase reduction effectively captures the dynamics of stochastic traveling pulses

Abstract

We consider synchronization by noise for stochastic partial differential equations which support traveling pulse solutions, such as the FitzHugh-Nagumo equation. We show that any two pulse-like solutions which start from different positions but are forced by the same realization of a multiplicative noise, converge to each other in probability on a time scale $\sigma^{-2} \ll t \ll \exp(\sigma^{-2})$, where $\sigma$ is the noise amplitude. The noise is assumed to be Gaussian, white in time, colored and periodic in space, and non-degenerate only in the lowest Fourier mode. The proof uses the method of phase reduction, which allows one to describe the dynamics of the stochastic pulse only in terms of its position. The position is shown to synchronize building upon existing results, and the validity of the phase reduction allows us to transfer the synchronization back to the full solution.