Transition between chaotic and stochastic universality classes of kinetic roughening

TL;DR

This paper investigates how the nature of fluctuations in non-equilibrium systems, specifically in the Kuramoto-Sivashinsky equation, can cause a transition between different universality classes of kinetic roughening, even when critical exponents remain unchanged.

Contribution

It demonstrates that the physical origin of fluctuations (chaotic or stochastic) can induce a transition between universality classes by altering the probability distribution function.

Findings

Transition occurs at non-zero noise amplitude

Universality class change without exponent variation

Potential for experimental verification

Abstract

The dynamics of non-equilibrium spatially extended systems are often dominated by fluctuations, due to e.g.\ deterministic chaos or to intrinsic stochasticity. This reflects into generic scale invariant or kinetic roughening behavior that can be classified into universality classes defined by critical exponent values and by the probability distribution function (PDF) of field fluctuations. Suitable geometrical constraints are known to change secondary features of the PDF while keeping the values of the exponents unchanged, inducing universality subclasses. Working on the Kuramoto-Sivashinsky equation as a paradigm of spatiotemporal chaos, we show that the physical nature of the prevailing fluctuations (chaotic or stochastic) can also change the universality class while respecting the exponent values, as the PDF is substantially altered. This transition takes place at a non-zero value of the stochastic noise amplitude and may be suitable for experimental verification.