Emergence of an Ising critical regime in the clustering of 1D soft matter revealed through string variables

TL;DR

This paper demonstrates that classical 1D soft matter systems exhibit an Ising critical regime during clustering, revealing a phase transition analogous to quantum systems, with observable thermodynamic signatures.

Contribution

It shows that classical 1D soft matter can display Ising critical behavior through string variables, extending quantum clustering insights to classical fluids.

Findings

Identification of Ising critical regime in classical 1D soft matter

Observation of an anomalous low-temperature specific heat peak

Mapping of particle clustering to a classical Ising model

Abstract

Soft matter systems are renowned for being able to display complex emerging phenomena such as clustering phases. Recently, a surprising quantum phase transition has been revealed in a one-dimensional (1D) system composed of bosons interacting via a pairwise soft potential in the continuum. It was shown that the spatial coordinates undergoing two-particle clustering could be mapped into quantum spin variables of a 1D transverse Ising model. In this work we investigate the manifestation of an analogous critical phenomenon in 1D classical fluids of soft particles in the continuum. In particular, we study the low-temperature behavior of three different classical models of 1D soft matter, whose inter-particle interactions allow for clustering. The same string variables highlight that, at the commensurate density for the two-particle cluster phase, the peculiar pairing of neighboring soft particles can be nontrivially mapped onto a 1D discrete classical Ising model. We also observe a related phenomenon, namely the presence of an anomalous peak in the low-temperature specific heat, thus indicating the emergence of Schottky phenomenology in a non-magnetic fluid.