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(307) Production(s) de BERTHIER L.


Stable glassy configurations of the KobAndersen model using swap Monte Carlo
Auteur(s): Parmar A. D. S., Guiselin B., Berthier L.
(Article) Publié:
The Journal Of Chemical Physics, vol. p.134505 (2020)
Texte intégral en Openaccess :
Ref HAL: hal02986292_v1
Ref Arxiv: 2006.10377
DOI: 10.1063/5.0020208
Ref. & Cit.: NASA ADS
Exporter : BibTex  endNote
Résumé: The swap Monte Carlo algorithm allows the preparation of highly stable glassy configurations for a number of glassformers, but is inefficient for some models, such as the much studied binary KobAndersen (KA) mixture. We have recently developed generalisations to the KA model where swap can be very effective. Here, we show that these models can in turn be used to considerably enhance the stability of glassy configurations in the original KA model at no computational cost. We successfully develop several numerical strategies both in and out of equilibrium to achieve this goal and show how to optimise them. We provide several physical measurements indicating that the proposed algorithms considerably enhance mechanical and thermodynamic stability in the KA model, including a transition towards brittle yielding behaviour. Our results thus pave the way for future studies of stable glasses using the KA model.



Glasses and aging: A Statistical Mechanics Perspective
Auteur(s): Arceri Francesco, Landes François, Berthier L., Biroli Giulio
(Document sans référence bibliographique) Texte intégral en Openaccess :
Ref HAL: hal02942375_v1
Ref Arxiv: 2006.09725
Ref. & Cit.: NASA ADS
Exporter : BibTex  endNote
Résumé: We review the field of the glass transition, glassy dynamics and aging from a statistical mechanics perspective. We give a brief introduction to the subject and explain the main phenomenology encountered in glassy systems, with a particular emphasis on spatially heterogeneous dynamics. We review the main theoretical approaches currently available to account for these glassy phenomena, including recent developments regarding meanfield theory of liquids and glasses, novel computational tools, and connections to the jamming transition. Finally, the physics of aging and offequilibrium dynamics exhibited by glassy materials is discussed.
Commentaires: 50 pages, 24 figs. This is an updated version of a chapter initially written in 2009 for the Encyclopedia of Complexity and Systems Science (Springer)



How to "measure" a structural relaxation time that is too long to be measured?
Auteur(s): Berthier L., Ediger Mark d.
(Article) Publié:
The Journal Of Chemical Physics, vol. p.044501 (2020)
Texte intégral en Openaccess :
Ref HAL: hal02986282_v1
Ref Arxiv: 2005.06520
DOI: 10.1063/5.0015227
Ref. & Cit.: NASA ADS
Exporter : BibTex  endNote
Résumé: It has recently become possible to prepare ultrastable glassy materials characterised by structural relaxation times which vastly exceed the duration of any feasible experiment. Similarly, new algorithms have led to the production of ultrastable computer glasses. Is it possible to obtain a reliable estimate of a structural relaxation time that is too long to be measured? We review, organise, and critically discuss various methods to estimate very long relaxation times. We also perform computer simulations of three dimensional ultrastable hard spheres glasses to test and quantitatively compare some of these methods for a single model system. The various estimation methods disagree significantly and it is not yet clear how to accurately estimate extremely long relaxation times.



Ultrastable metallic glasses in silico
Auteur(s): Parmar A. D. S., Ozawa M., Berthier L.
(Article) Publié:
Physical Review Letters, vol. p.085505 (2020)
Texte intégral en Openaccess :
Ref HAL: hal02986302_v1
PMID 32909772
Ref Arxiv: 2002.01317
DOI: 10.1103/PhysRevLett.125.085505
WoS: 000561724800007
Ref. & Cit.: NASA ADS
Exporter : BibTex  endNote
2 Citations
Résumé: We devise a generic strategy and simple numerical models for multicomponent metallic glasses for which the swap Monte Carlo algorithm can produce highly stable equilibrium configurations equivalent to experimental systems cooled more than $10^7$ times slower than in conventional simulations. This paves the way for a deeper understanding of thermodynamic, dynamic, and mechanical properties of metallic glasses. As a first application, we extend configurational entropy measurements down to the experimental glass temperature, and demonstrate a qualitative evolution of the mechanical response of metallic glasses of increasing stability towards brittleness.



Finitedimensional vestige of spinodal criticality above the dynamical glass transition
Auteur(s): Berthier L., Charbonneau Patrick, Kundu Joyjit
(Article) Publié:
Physical Review Letters, vol. p.108001 (2020)
Texte intégral en Openaccess :
Ref HAL: hal02986305_v1
PMID 32955295
Ref Arxiv: 1912.11510
DOI: 10.1103/PhysRevLett.125.108001
WoS: 000564051900012
Ref. & Cit.: NASA ADS
Exporter : BibTex  endNote
5 Citations
Résumé: Finitedimensional signatures of spinodal criticality are notoriously difficult to come by. The dynamical transition of glassforming liquids, first described by modecoupling theory, is a spinodal instability preempted by thermally activated processes that also limit how close the instability can be approached. We combine numerical tools to directly observe vestiges of the spinodal criticality in finitedimensional glass formers. We use the swap Monte Carlo algorithm to efficiently thermalise configurations beyond the modecoupling crossover, and analyze their dynamics using a scheme to screen out activated processes, in spatial dimensions ranging from $d=3$ to $d=9$. We observe a strong softening of the meanfield squareroot singularity in $d=3$ that is progressively restored as $d$ increases above $d=8$, in surprisingly good agreement with perturbation theory.



Randomfield Ising model criticality in a glassforming liquid
Auteur(s): Guiselin B., Berthier L., Tarjus Gilles
(Article) Publié:
Physical Review E, vol. 102 p.042129 (2020)
Texte intégral en Openaccess :
Ref HAL: hal02925447_v1
Ref Arxiv: 2004.10555
DOI: 10.1103/PhysRevE.102.042129
WoS: WOS:000582805100002
Ref. & Cit.: NASA ADS
Exporter : BibTex  endNote
Résumé: We use computer simulations to investigate the extended phase diagram of a supercooled liquid linearly coupled to a quenched reference configuration. An extensive finitesize scaling analysis demonstrates the existence of a randomfield Ising model (RFIM) critical point and of a firstorder transition line, in agreement with fieldtheoretical approaches. The dynamics in the vicinity of this critical point resembles the peculiar activated scaling of RFIMlike systems, and the overlap autocorrelation displays a logarithmic stretching. Our study firmly establishes the RFIM criticality in threedimensional supercooled liquids at equilibrium.



On the overlap between configurations in glassy liquids
Auteur(s): Guiselin B., Tarjus Gilles, Berthier L.
(Article) Publié:
The Journal Of Chemical Physics, vol. 153 p.224502 (2020)
Texte intégral en Openaccess :
Ref HAL: hal02925446_v1
Ref Arxiv: 2007.07625
DOI: 10.1063/5.0022614
WoS: WOS:000600047800001
Ref. & Cit.: NASA ADS
Exporter : BibTex  endNote
Résumé: The overlap, or similarity, between liquid configurations is at the core of the meanfield description of the glass transition, and remains a useful concept when studying threedimensional glassforming liquids. In liquids, however, the overlap involves a tolerance, typically of a fraction $a/\sigma$ of the interparticle distance, associated with how precisely similar two configurations must be for belonging to the same physically relevant "state". Here, we systematically investigate the dependence of the overlap fluctuations and of the resulting phase diagram when the tolerance is varied over a large range. We show that while the location of the dynamical and thermodynamic glass transition (if present) are independent of $a/\sigma$, that of the critical point associated with a transition between a low and a highoverlap phases in the presence of an applied source nontrivially depends on the value of $a/\sigma$. We rationalize our findings by using liquidstate theory and the hypernetted chain (HNC) approximation for correlation functions. In addition, we confirm the theoretical trends by studying a threedimensional glassformer by computer simulations. We show in particular that a specific choice of $a/\sigma$ maximizes the temperature of the critical point, pushing it up in a liquid region where viscosity is low and computer investigations are easier due to a significantly faster equilibration.
