Extreme statistics and volume fluctuations in a confined one-dimensional gas

TL;DR

This paper investigates volume fluctuations in a one-dimensional classical gas under external potential, revealing non-Gaussian behavior described by generalized extreme value distributions, with implications for thermodynamics.

Contribution

It demonstrates that volume fluctuations in a non-interacting 1D gas are non-Gaussian and follow generalized extreme value distributions, linking shape parameters to external forces.

Findings

Volume fluctuations are non-Gaussian despite no interactions.

Fluctuations follow generalized extreme value distributions.

Gaussian fluctuations occur under strong compression.

Abstract

We consider the statistics of volume fluctuations in a one-dimensional classical gas of non-interacting particles confined by a piston, and subjected to an arbitrary external potential. We show that despite the absence of interactions between particles, volume fluctuations of the gas are non-Gaussian, and are described by generalized extreme value distributions. The continuous shape parameter of these distributions is related to the ratio between the force acting on the piston, and the force acting on the particles. Gaussian fluctuations are recovered in the strong compression limit, when the effect of the external potential becomes negligible. Consequences for the thermodynamics are also discussed.