KPZ scaling in topological mixing

TL;DR

This paper investigates the statistical properties of topological chaos in fluid flows, demonstrating that the variance of the braiding exponent follows KPZ universality class behavior, linking topological mixing with growth models.

Contribution

It introduces a novel analysis of the braiding exponent's variance in topological chaos, connecting it to KPZ universality and growth models via matrix representations.

Findings

Variance of braiding exponent exhibits KPZ universality class behavior.

Random stirring protocol relates to growth of random heaps in ballistic deposition.

Topological chaos characterized by statistical properties similar to nonstationary growth models.

Abstract

In the spirit of recent works on topological chaos generated by sequential rotation of infinitely thin stirrers placed in a viscous liquid, we consider the statistical properties of braiding exponent which quantitatively characterizes the chaotic behavior of advected particles in two-dimensional flows. We pay a special attention to the random stirring protocol and study the time-dependent behavior of the variance of the braiding exponent. We show that this behavior belongs to the Kardar-Parisi-Zhang universality class typical for models of nonstationary growth. Using the matrix (Magnus) representation of the braid group generators, we relate the random stirring protocol with the growth of random heap generated by a ballistic deposition.