Disordered hyperuniformity in two-component non-additive hard disk plasmas

TL;DR

This paper investigates a two-component plasma of non-additive hard disks with Coulomb interactions, revealing how hyperuniformity influences phase behavior, fluctuations, and entropy, and showing that individual components are not hyperuniform despite the system's overall hyperuniformity.

Contribution

It demonstrates the presence of hyperuniformity in a two-component plasma with non-additive hard disks and explores its effects on phase separation, fluctuations, and entropy, highlighting the non-multihyperuniform nature of individual components.

Findings

Long-wavelength density fluctuations are suppressed due to Coulomb repulsion.

Hyperuniformity modifies the critical behavior and dampens concentration fluctuations.

The system's configurational entropy decrease is linked to many-particle contributions.

Abstract

We study the behavior of a two-component plasma made up of non-additive hard disks with a logarithmic Coulomb interaction. Due to the Coulomb repulsion, long-wavelength total density fluctuations are suppressed and the system is globally hyperuniform. Short-range volume effects lead to phase separation or to hetero-coordination for positive or negative non-additivities, respectively. These effects compete with the hidden long-range order imposed by hyperuniformity. As a result, the critical behavior of the mixture is modified, with long-wavelength concentration fluctuations partially damped when the system is charged. It is also shown that the decrease of configurational entropy due to hyperuniformity originates from contributions beyond the two-particle level. Finally, despite global hyperuniformity, we show that in our system, the spatial configuration associated with each component separately is not hyperuniform, i.e., the system is not "multihyperuniform."