Unified analysis of topological defects in 2D systems of active and passive disks
| Autor: | Pasquale Digregorio, Demian Levis, Leticia F. Cugliandolo, Giuseppe Gonnella, Ignacio Pagonabarraga |
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| Přispěvatelé: | Centre Européen de Calcul Atomique et Moléculaire (CECAM), École normale supérieure de Lyon (ENS de Lyon)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Universitat de Barcelona (UB), Università degli studi di Bari Aldo Moro = University of Bari Aldo Moro (UNIBA), Laboratoire de Physique Théorique et Hautes Energies (LPTHE), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2021 |
| Předmět: |
[PHYS]Physics [physics]
Statistical Mechanics (cond-mat.stat-mech) behavior FOS: Physical sciences General Chemistry Condensed Matter - Soft Condensed Matter Condensed Matter Physics metastability Condensed Matter::Soft Condensed Matter percolation statistics crystals Soft Condensed Matter (cond-mat.soft) grain-boundary theory lennard-jones transitions Condensed Matter - Statistical Mechanics random-cluster model lattice |
| Zdroj: | Soft Matter Soft Matter, 2022, 18 (3), pp.566 |
| ISSN: | 1744-6848 1744-683X |
| Popis: | We provide a comprehensive quantitative analysis of localized and extended topological defects in the steady state of 2D passive and active repulsive Brownian disk systems. We show that, both in and out-of-equilibrium, the passage from the solid to the hexatic is driven by the unbinding of dislocations, in quantitative agreement with the KTHNY singularity. Instead, although disclinations dissociate as soon as the liquid phase appears, extended clusters of defects largely dominate below the solid-hexatic critical line. The latter percolate in the liquid phase very close to the hexatic-liquid transition, both for continuous and discontinuous transitions, in the homogeneous liquid regime. At critical percolation the clusters of defects are fractal with statistical and geometric properties that, within our numerical accuracy, are independent of the activity and compatible with the universality class of uncorrelated critical percolation. We also characterize the spatial organization of different kinds of point-like defects and we show that the disclinations are not free, but rather always very near more complex defect structures. At high activity, the bulk of the dense phase generated by Motility-Induced Phase Separation is characterized by a density of point-like defects, and statistics and morphology of defect clusters, set by the amount of activity and not the packing fraction. Hexatic domains within the dense phase are separated by grain-boundaries along which a finite network of topological defects resides, interrupted by gas bubbles in cavitation. The fractal dimension of this network diminishes for increasing activity. This structure is dynamic in the sense that the defect network allows for an unzipping mechanism that leaves free space for gas bubbles to appear, close, and even be released into the dilute phase. Comment: 29 pages, 35 figures |
| Databáze: | OpenAIRE |
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