Dynamic Scaling of Coupled Nonequilibrium Interfaces

TL;DR

This paper introduces a discrete model for coupled nonequilibrium interfaces, deriving continuum equations and analyzing their scaling behavior, revealing KPZ exponents in symmetric cases and increased roughness otherwise.

Contribution

It presents a new discrete model and continuum equations for coupled interfaces, with analytical and numerical analysis of their scaling properties.

Findings

KPZ exponents recovered in symmetric coupling

Increased roughness observed when one interface fluctuates independently

Continuum equations accurately describe the model's fluctuations

Abstract

We propose a simple discrete model to study the nonequilibrium fluctuations of two locally coupled 1+1 dimensional systems (interfaces). Measuring numerically the tilt-dependent velocity we construct a set of stochastic continuum equations describing the fluctuations in the model The scaling predicted by the equations are studied analytically using dynamic renormalization group and compared with simulation results. When the coupling is symmetric, the well known KPZ exponents are recovered. If one of the systems is fluctuating independently, an increase in the roughness exponent is observed for the other one.