Dynamics of stochastic oscillator chains with harmonic and FPUT potentials

TL;DR

This paper introduces a stochastic chain model of oscillators with harmonic and FPUT potentials, exploring how local interactions and bath temperatures influence long-range effects and non-equilibrium dynamics.

Contribution

It presents a novel stochastic oscillator chain model with mixed potentials and investigates the impact of different hopping rules and boundary conditions on system behavior.

Findings

Long-range interactions emerge from local index-space interactions.

Hopping rules significantly affect non-equilibrium steady states.

Boundary temperature differences induce energy flow and complex dynamics.

Abstract

Inspired by recent studies on deterministic oscillator models, we introduce a stochastic one-dimensional model for a chain of interacting particles. The model consists of $N$ oscillators performing continuous-time random walks on the integer lattice $\mathbb{Z}$ with exponentially distributed waiting times. The oscillators are bound by confining forces to two particles that do not move, placed at positions $x_0$ and $x_{N+1}$, respectively, and they feel the presence of baths with given inverse temperatures: $\beta_L$ to the left, $\beta_B$ in the middle, and $\beta_R$ to the right. Each particle has an index and interacts with its nearest neighbors in index space through either a quadratic potential or a Fermi-Pasta-Ulam-Tsingou type coupling. This local interaction in index space can give rise to effective long-range interactions on the spatial lattice, depending on the instantaneous configuration. Particle hopping rates are governed either by the Metropolis rule or by a modified version that breaks detailed balance at the interfaces between regions with different baths.