Denser-than-crystalline disordered polydisperse ellipse packings
Abstract
By employing SWAP Monte Carlo moves during slow Lubachevsky-Stillinger-like particle growth, we generate well-thermalized disordered jammed ellipse packings for a wide range of particle aspect ratios α and maximum/minimum particle-diameter ratios λ. For λ> λxtal(α), the packings are denser than the perfect monodisperse ellipse crystal (ϕxtalmono = π/2√3 ≃ 0.9069) despite lacking any obvious long-range structural order; we find that λxtal(α) remains below $2.88$ over the range 1 ≤ α≤ 5, and drops below $1.65$ for α≃ 1.2. These disordered ϕ> ϕxtalmono packings are the first of their kind reported for anisotropic particles. Multiscale analyses reveal that their characteristic structural motifs are strongly α- and λ-dependent, but none of the examined metrics change sharply as the λ= λxtal(α) boundary is crossed. For example, we find that packings with α≃ 1.2 and λ≃ λxtal(α) exhibit a fractionated-hexatic-plastic-polycrystalline structure that (like that of the recently-reported ideal disk glasses) can be exactly-isostatic, triangulated, and effectively-hyperuniform with respect to packing-fraction fluctuations. In contrast, even-denser packings with larger α and λ have none of these properties.
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BibTeX
@misc{trlak2026denserthancrystalline,
title = {{Denser-than-crystalline disordered polydisperse ellipse packings}},
author = {Kinsley G. Trlak and Dewni S. de Silva and Salvatore Torquato and Robert S. Hoy},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.20953},
eprint = {2610.20953},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.20953},
}
RIS
TY - UNPB
TI - Denser-than-crystalline disordered polydisperse ellipse packings
AU - Kinsley G. Trlak
AU - Dewni S. de Silva
AU - Salvatore Torquato
AU - Robert S. Hoy
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.20953
UR - https://arxiv.org/abs/2610.20953
AB - By employing SWAP Monte Carlo moves during slow Lubachevsky-Stillinger-like particle growth, we generate well-thermalized disordered jammed ellipse packings for a wide range of particle aspect ratios α and maximum/minimum particle-diameter ratios λ. For λ> λ_xtal(α), the packings are denser than the perfect monodisperse ellipse crystal (ϕ_xtal^mono = π/2√3 ≃ 0.9069) despite lacking any obvious long-range structural order; we find that λ_xtal(α) remains below $2.88$ over the range 1 ≤ α≤ 5, and drops below $1.65$ for α≃ 1.2. These disordered ϕ> ϕ_xtal^mono packings are the first of their kind reported for anisotropic particles. Multiscale analyses reveal that their characteristic structural motifs are strongly α- and λ-dependent, but none of the examined metrics change sharply as the λ= λ_xtal(α) boundary is crossed. For example, we find that packings with α≃ 1.2 and λ≃ λ_xtal(α) exhibit a fractionated-hexatic-plastic-polycrystalline structure that (like that of the recently-reported ideal disk glasses) can be exactly-isostatic, triangulated, and effectively-hyperuniform with respect to packing-fraction fluctuations. In contrast, even-denser packings with larger α and λ have none of these properties.
ER -