# Geometric effects in random assemblies of ellipses

## TL;DR

This study investigates how the shape and density of elliptical particles influence the structure of their assemblies in two dimensions, revealing key geometric effects and differences from three-dimensional systems.

## Contribution

It provides a comprehensive analysis of geometric effects in 2D assemblies of ellipses, including correlations between morphological measures and comparisons with 3D findings.

## Key findings

- Differences from 3D assemblies across aspect ratios and packing fractions
- Identification of correlations between morphological measures
- A reference dataset for geometric effects in 2D elliptical assemblies

## Abstract

Assemblies of anisotropic particles commonly appear in studies of active many-body systems. However, in two dimensions, the geometric ramifications of the finite density of such objects are not entirely understood. To fully characterize these effects, we perform an in-depth study of random assemblies generated by a slow compression of frictionless elliptical particles. The obtained configurations are then analysed using the Set Voronoi tessellation which takes the particle shape into the account. Not only that we analyse most scalar and vectorial morphological measures, which are commonly discussed in the literature or which have been recently addressed in experiments, but also systematically explore the correlations between them. While in a limited range of parameters similarities with findings in 3D assemblies could be identified, important differences are found when a broad range of aspect ratios and packing fractions are considered. The data discussed in this study should thus provide a unique reference set such that geometric effects and differences from random assemblies could be clearly identified in more complex systems, including ones with soft and active particles that are typically found in biological systems.