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Dynamique et rhéologie des fluides complexes (gels, polymères, mousses, colloïdes)
(23) Production(s) de l'année 2023
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Deformation and fracture of silicate glasses: New insights from atomistic simulations
Auteur(s): Kob W.
Conférence invité: GOMD 2023 (New Orleans, US, 2023-06-04)
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Two-Dimensional Crystals far from Equilibrium
Auteur(s): Galliano Leonardo, Cates Michael, Berthier L.
(Article) Publié:
Physical Review Letters, vol. 131 p.047101 (2023)
Ref HAL: hal-04184847_v1
DOI: 10.1103/PhysRevLett.131.047101
Exporter : BibTex | endNote
Résumé: When driven by nonequilibrium fluctuations, particle systems may display phase transitions and physical behaviour with no equilibrium counterpart. We study a two-dimensional particle model initially proposed to describe driven non-Brownian suspensions undergoing nonequilibrium absorbing phase transitions. We show that when the transition occurs at large density, the dynamics produces long-range crystalline order. In the ordered phase, long-range translational order is observed because equipartition of energy is lacking, phonons are suppressed, and density fluctuations are hyperuniform. Our study offers an explicit microscopic model where nonequilibrium violations of the Mermin-Wagner theorem stabilize crystalline order in two dimensions.
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Intermittent relaxation and avalanches in extremely persistent active matter
Auteur(s): Keta Y.-E., Mandal Rituparno, Sollich Peter, Jack Robert, Berthier L.
(Article) Publié:
Soft Matter, vol. 19 p.3871-3883 (2023)
Texte intégral en Openaccess :
Ref HAL: hal-04141015_v1
Ref Arxiv: 2212.09836
DOI: 10.1039/D3SM00034F
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: We use numerical simulations to study the dynamics of dense assemblies of self-propelled particles in the limit of extremely large, but finite, persistence times. In this limit, the system evolves intermittently between mechanical equilibria where active forces balance interparticle interactions. We develop an efficient numerical strategy allowing us to resolve the statistical properties of elastic and plastic relaxation events caused by activity-driven fluctuations. The system relaxes via a succession of scale-free elastic events and broadly distributed plastic events that both depend on the system size. Correlations between plastic events lead to emergent dynamic facilitation and heterogeneous relaxation dynamics. Our results show that dynamical behaviour in extremely persistent active systems is qualitatively similar to that of sheared amorphous solids, yet with some important differences.
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Predicting Dynamic Heterogeneity in Glass-Forming Liquids by Physics-informed Machine Learning
Auteur(s): Jung G., Biroli Giulio, Berthier L.
(Article) Publié:
Physical Review Letters, vol. 130 p.238202 (2023)
Texte intégral en Openaccess :
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Dynamic Gardner cross-over in a simple glass
Auteur(s): Liao Qinyi, Berthier L., Zhou Hai-Jun, Xu Ning
(Article) Publié:
Proceedings Of The National Academy Of Sciences Of The United States Of America, vol. 120 p.e2218218120 (2023)
Texte intégral en Openaccess :
Ref HAL: hal-04140969_v1
Ref Arxiv: 2209.10917
DOI: 10.1073/pnas.2218218120
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: The criticality of the jamming transition responsible for amorphous solidification has been theoretically linked to the marginal stability of a thermodynamic Gardner phase. While the critical exponents of jamming appear independent of the preparation history, the pertinence of Gardner physics far from equilibrium is an open question. To fill this gap, we numerically study the nonequilibrium dynamics of hard disks compressed toward the jamming transition using a broad variety of protocols. We show that dynamic signatures of Gardner physics can be disentangled from the aging relaxation dynamics. We thus define a generic dynamic Gardner cross-over regardless of the history. Our results show that the jamming transition is always accessed by exploring increasingly complex landscape, resulting in anomalous microscopic relaxation dynamics that remains to be understood theoretically.
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Two-step devitrification of ultrastable glasses
Auteur(s): Herrero C., Scalliet C., Ediger M., Berthier L.
(Article) Publié:
Proceedings Of The National Academy Of Sciences Of The United States Of America, vol. 120 p. (2023)
Texte intégral en Openaccess :
Ref HAL: hal-04117704_v1
Ref Arxiv: 2210.04775
DOI: 10.1073/pnas.2220824120
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: The discovery of ultrastable glasses raises novel challenges about glassy systems. Recent experiments studied the macroscopic devitrification of ultrastable glasses into liquids upon heating but lacked microscopic resolution. We use molecular dynamics simulations to analyze the kinetics of this transformation. In the most stable systems, devitrification occurs after a very large time, but the liquid emerges in two steps. At short times, we observe the rare nucleation and slow growth of isolated droplets containing a liquid maintained under pressure by the rigidity of the surrounding glass. At large times, pressure is released after the droplets coalesce into large domains, which accelerates devitrification. This two-step process produces pronounced deviations from the classical Avrami kinetics and explains the emergence of a giant lengthscale characterizing the devitrification of bulk ultrastable glasses. Our study elucidates the nonequilibrium kinetics of glasses following a large temperature jump, which differs from both equilibrium relaxation and aging dynamics, and will guide future experimental studies.
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Modern computational studies of the glass transition
Auteur(s): Berthier L., Reichman David
(Article) Publié:
-Nature Reviews Physics, vol. 5 p.102-116 (2023)
Texte intégral en Openaccess :
Ref HAL: hal-04117501_v1
Ref Arxiv: 2208.02206
DOI: 10.1038/s42254-022-00548-x
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: The physics of the glass transition and amorphous materials continues to attract the attention of a wide research community after decades of effort. Supercooled liquids and glasses have been studied numerically since the advent of molecular dynamics and Monte Carlo simulations in the last century. Computer studies have greatly enhanced both experimental discoveries and theoretical developments and constitute an active and continually expanding research field. Our goal in this review is to provide a modern perspective on this area. We describe the need to go beyond canonical methods to attack a problem that is notoriously difficult in terms of time scales, length scales, and physical observables. We first summarise recent algorithmic developments to achieve enhanced sampling and faster equilibration using replica exchange methods, cluster and swap Monte Carlo algorithms, and other techniques. We then review some major recent advances afforded by these novel tools regarding the statistical mechanical description of the liquid-to-glass transition as well as the mechanical, vibrational and thermal properties of the glassy solid. We finally describe some important challenges for future research.
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