Overload wave-memory induces amnesia of a self-propelled particle

TL;DR

This paper investigates how the accumulation of information in the wavefield of a self-propelled droplet system leads to a loss of memory, effectively turning the dynamics into a memory-less process, with implications for understanding active matter.

Contribution

It demonstrates experimentally and numerically that wavefield information causes amnesia in a self-propelled particle, introducing an effective temperature and a wavefield minimization principle.

Findings

Wavefield information accumulation induces loss of time correlations.

The dynamics can be modeled as a memory-less process.

An effective temperature describes the particle-wavefield interaction.

Abstract

Information storage is a key element of autonomous, out-of-equilibrium dynamics, especially for biological and synthetic active matter. In synthetic active matter however, the implementation of internal memory in self-propelled systems is often absent, limiting our understanding of memory-driven dynamics. Recently, a system comprised of a droplet generating its guiding wavefield appeared as a prime candidate for such investigations. Indeed, the wavefield, propelling the droplet, encodes information about the droplet trajectory and the amount of information can be controlled by a single scalar experimental parameter. In this work, we show numerically and experimentally that the accumulation of information in the wavefield induces the loss of time correlations, where the dynamics can then be described by a memory-less process. We rationalize the resulting statistical behaviour by defining an effective temperature for the particle dynamics where the wavefield acts as a thermostat of large dimensions, and by evidencing a minimization principle of the generated wavefield.