# Orientational correlations in fluids with quenched disorder

## TL;DR

This study uses Monte Carlo simulations to analyze how quenched disorder affects orientational correlations in 2D fluid models, revealing non-monotonic behaviors near phase transitions that can be experimentally observed.

## Contribution

It introduces a novel disorder-averaged correlation function for local orientation and explores its behavior near fluid-solid transitions in disordered systems.

## Key findings

- Correlations show non-monotonic behavior near phase transition.
- Disorder-averaged correlations can be experimentally measured.
- Novel correlation function analogous to Edwards-Anderson in spin systems.

## Abstract

Snapshots of colloidal particles moving on disordered two-dimensional substrates can be used to extract equal-time many-body correlations in their positions. To understand the systematics of these correlations, we perform Monte Carlo simulations of a two-dimensional model fluid placed in a quenched disordered background. We use configurations generated from these simulations to compute translational and orientational two-point correlations at equal time, concentrating on correlations in local orientational order as a function of density and disorder strength. We calculate both the disorder averaged version of conventional two-point correlation functions for orientational order, as well as the disorder averaged version of a novel correlation function of time-averaged disorder-induced inhomogeneities in local orientation analogous to the Edwards-Anderson correlation function in spin systems. We demonstrate that these correlations can exhibit interesting non-monotonic behavior in proximity to the underlying fluid-solid transition and suggest that this prediction should be experimentally accessible.