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Dynamique et rhéologie des fluides complexes (gels, polymères, mousses, colloïdes)
(2) Production(s) de l'année 2024
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Dynamic heterogeneity at the experimental glass transition predicted by transferable machine learning 
Auteur(s): Jung G., Biroli Giulio, Berthier L.
(Article) Publié:
Physical Review B, vol. 109 p.064205 (2024)
Texte intégral en Openaccess : 
Ref HAL: hal-04514863_v1
Ref Arxiv: 2310.20252
DOI: 10.1103/PhysRevB.109.064205
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: We develop a machine learning model, which predicts structural relaxation from amorphous supercooled liquid structures. The trained networks are able to predict dynamic heterogeneity across a broad range of temperatures and time scales with excellent accuracy and transferability. We use the network transferability to predict dynamic heterogeneity down to the experimental glass transition temperature Tg, where structural relaxation cannot be analyzed using molecular dynamics simulations. The results indicate that the strength, the geometry, and the characteristic length scale of the dynamic heterogeneity evolve much more slowly near Tg compared to their evolution at higher temperatures. Our results show that machine learning techniques can provide physical insights on the nature of the glass transition that cannot be gained using conventional simulation techniques.
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Collective Relaxation Dynamics in a Three-Dimensional Lattice Glass Model
Auteur(s): Nishikawa Y., Berthier L.
(Article) Publié:
Physical Review Letters, vol. 132 p.067101 (2024)
Texte intégral en Openaccess :
Ref HAL: hal-04453684_v1
Ref Arxiv: 2307.08110
DOI: 10.1103/PhysRevLett.132.067101
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: We numerically elucidate the microscopic mechanisms controlling the relaxation dynamics of a three-dimensional lattice glass model that has static properties compatible with the approach to a random first-order transition. At low temperatures, the relaxation is triggered by a small population of particles with low-energy barriers forming mobile clusters. These emerging quasiparticles act as facilitating defects responsible for the spatially heterogeneous dynamics of the system, whose characteristic lengthscales remain strongly coupled to thermodynamic fluctuations. We compare our findings both with existing theoretical models and atomistic simulations of glass-formers.
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