Experimental observation of violent relaxation and the formation of out-of-equilibrium quasi-stationary states

TL;DR

This paper presents a tabletop experiment that simulates violent relaxation in astrophysical systems, enabling direct observation of out-of-equilibrium state formation and phase space mixing, which are otherwise inaccessible due to cosmic time scales.

Contribution

It introduces a novel experimental setup that models gravitational relaxation processes, allowing controlled study of violent relaxation and out-of-equilibrium states.

Findings

Observation of phase space mixing and violent relaxation effects

Control over interaction strength and quantum effects in the model

Formation of a galaxy analogue in a laboratory setting

Abstract

Large scale structures in the Universe, ranging from globular clusters to entire galaxies, are the manifestation of relaxation to out-of-equilibrium states that are not described by standard statistical mechanics at equilibrium. Instead, they are formed through a process of a very different nature, i.e. violent relaxation. However, astrophysical time-scales are so large that it is not possible to directly observe these relaxation dynamics and therefore verify the details of the violent relaxation process. We develop a table-top experiment and model that allows us to directly observe effects such as mixing of phase space, and violent relaxation, leading to the formation of a table-top analogue of a galaxy. The experiment allows us to control a range of parameters, including the nonlocal (gravitational) interaction strength and quantum effects, thus providing an effective test-bed for gravitational models that cannot otherwise be directly studied in experimental settings.