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(326) Production(s) de BERTHIER L.
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On the relaxation dynamics of glass-forming systems: Insights from computer simulations 
Auteur(s): Chaudhuri Pinaki, Berthier L., Sastry Srikanth, Kob W.
(Article) Publié:
Aip Conference Proceedings, vol. 1091 p.95 (2009)
Texte intégral en Openaccess : 
Ref HAL: hal-00533613_v1
Ref Arxiv: 0811.0223
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: We discuss the relaxation dynamics of a simple lattice gas model for glass-forming systems and show that with increasing density of particles this dynamics slows down very quickly. By monitoring the trajectory of tagged particles we find that their motion is very heterogeneous in space and time, leading to regions in space in which there is a fast dynamics and others in which it is slow. We determine how the geometric properties of these quickly relaxing regions depend on density and time. Motivated by this heterogeneous hopping dynamics, we use a simple model, a variant of a continuous time random walk, to characterize the relaxation dynamics. In particular we find from this model that for large displacements the self part of the van Hove function shows an exponential tail, in agreement with recent findings from experiments and simulations of glass-forming systems.
Commentaires: Paper presented at the 10th Granada Conference on Computational and Statistical physics Journal: AIP Conf. Proc. 1091, 95 (2009)
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Static and dynamic properties of a reversible gel
Auteur(s): Hurtado Pablo, Chaudhuri Pinaki, Berthier L., Kob W.
(Article) Publié:
Aip Conference Proceedings, vol. 1091 p.166 (2009)
Texte intégral en Openaccess :
Ref HAL: hal-00533612_v1
Ref Arxiv: 0811.1447
Ref. & Cit.: NASA ADS
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Résumé: We study a microscopically realistic model of a physical gel and use computer simulations to investigate its static and dynamic properties at thermal equilibrium. The phase diagram comprises a sol phase, a coexistence region ending at a critical point, a gelation line, and an equilibrium gel phase unrelated to phase separation. The global structure of the gel is homogeneous, but the stress is supported by a fractal network. Gelation results in a dramatic slowing down of the dynamics, which can be used to locate the transition, which otherwise shows no structural signatures. Moreover, the equilibrium gel dynamics is highly heterogeneous as a result of the presence of particle families with different mobilities. An analysis of gel dynamics in terms of mobile and arrested particles allows us to elucidate several differences between the dynamics of equilibrium gels and that of glass-formers.
Commentaires: 9 pages, 7 figures, paper presented at the 10th Granada Seminar on Computational and Statistical Physics Journal: AIP Conf. Proc. 1091, 166 (2009)
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Probing the equilibrium dynamics of colloidal hard spheres above the mode-coupling glass transition
Auteur(s): Brambilla G., El masri Djamel, Pierno Matteo, Berthier L. , Cipelletti L., Petekidis George, B. Schofield Andrew
(Article) Publié:
Physical Review Letters, vol. 102 p.085703 (2009)
Texte intégral en Openaccess :
Ref HAL: hal-00323231_v2
PMID 19257755
Ref Arxiv: 0809.3401
DOI: 10.1103/PhysRevLett.102.085703
WoS: 000263816200034
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
290 Citations
Résumé: We use dynamic light scattering and computer simulations to study equilibrium dynamics and dynamic heterogeneity in concentrated suspensions of colloidal hard spheres. Our study covers an unprecedented density range and spans seven decades in structural relaxation time, $\ta$, including equilibrium easurements above $\phi_{\rm c}$, the location of the glass transition deduced from fitting our data to mode-coupling theory. Instead of falling out of equilibrium, the system remains ergodic above $\phi_{\rm c}$ and enters a new dynamical regime where $\ta$ increases with a functional form that was not anticipated by previous experiments, while the amplitude of dynamic heterogeneity grows slower than a power law with $\ta$, as found in molecular glass-formers close to the glass transition.
Commentaires: 4 pages, 3 figures, published in PRL 102 085703 (2009)
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A random walk description of the heterogeneous dynamics of colloidal gels
Auteur(s): Chaudhuri Pinaki, Gao G., Berthier L., Kilfoil M., Kob W.
(Article) Publié:
Journal Of Physics: Condensed Matter, vol. 20 p.244126 (2008)
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Fluctuation dissipation relations and effective temperatures out of equilibrium
Auteur(s): Berthier L.
Conférence invité: Fluctuations in out of equilibrium systems (Grenoble, FR, 2008-10-20)
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Understanding the glass transition using soft particles
Auteur(s): Berthier L.
Conference: Unitying concepts in glass physics (Kyoto, Japan, FR, 2008-11-24)
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Self diffusion and collective dynamics in glass forming liquids
Auteur(s): Berthier L.
Conference: Atelier Physique Statistique (Nancy, France, FR, 2008-05-21)
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