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(327) Production(s) de BERTHIER L.
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Aging and ultra-slow equilibration in concentrated colloidal hard spheres
Auteur(s): El masri Djamel, Pierno Matteo, Berthier L., Cipelletti L.
(Article) Publié:
Journal Of Physics: Condensed Matter, vol. 17 p.S3543-S3549 (2005)
DOI: 10.1088/0953-8984/17/45/046
WoS: 000235394200047
39 Citations
Résumé: We study the dynamic behaviour of concentrated colloidal hard spheres using time resolved correlation, a light scattering technique that can detect the slow evolution of the dynamics in out-of-equilibrium systems. Surprisingly, equilibrium is reached a very loner time after sample initialization. the nonstationary regime lasting up to three orders of magnitude more than the relaxation time of the system. Before reaching equilibrium, the system displays unusual ageing behaviour. The intermediate scattering function decays faster than exponentially and its relaxation time evolves non-monotonically with sample age
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Temperature cycles in the Heisenberg spin glass
Auteur(s): Berthier L., Young A.P.
(Article) Publié:
Physical Review B, vol. 71 p.214429 (2005)
Résumé: We study numerically the nonequilibrium dynamics of the three-dimensional Heisenberg Edwards-Anderson spin glass submitted to protocols during which temperature is shifted or cycled within the spin glass phase. We show that (partial) rejuvenation and (perfect) memory effects can be numerically observed and study both effects in detail. We quantitatively characterize their dependences on parameters such as the amplitude of the temperature changes, the time scale at which the changes are performed, and the cooling rates used to vary the temperature. We contrast our results both to those found numerically in the Ising version of the model, and to experimental results in different samples. We discuss the theoretical interpretations of our findings, arguing, in particular, that "full" rejuvenation can be observed in experiments even if temperature chaos is absent.
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Numerical study of a fragile three-dimensional kinetically constrained model
Auteur(s): Berthier L., Garrahan J.P.
(Article) Publié:
The Journal Of Physical Chemistry B, vol. 109 p.3578-3585 (2005)
Résumé: We numerically study the three-dimensional generalization of the kinetically constrained east model, the north-or-east-or-front (NEF) model. We characterize the equilibrium behavior of the NEF model in detail, measuring the temperature dependence of several quantities: alpha-relaxation time, distributions of relaxation times, dynamic susceptibility, dynamic correlation length, and four-point susceptibility. We show that the NEF model describes quantitatively experimental observations over an exceptionally wide range of time scales. We illustrate this by fitting experimental data obtained both in the mildly supercooled regime by optical Kerr effect and close to the glass transition by dielectric spectroscopy.
Commentaires: ISI Document Delivery No.: 900XH Times Cited: 7 Cited Reference Count: 48 English Article 1520-6106
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Length scale for the onset of Fickian diffusion in supercooled liquids
Auteur(s): Berthier L., Chandler D., Garrahan J.P.
(Article) Publié:
Europhysics Letters (Epl), vol. 69 p.320-326 (2005)
Résumé: The interplay between self-diffusion and excitation lines in space-time was recently studied in kinetically constrained models to explain the breakdown of the Stokes-Einstein law in supercooled liquids. Here, we further examine this interplay and its manifestation in incoherent scattering functions. In particular, we establish a dynamic length scale below which Fickian diffusion breaks down, as is observed in experiments and simulations. We describe the temperature dependence of this length scale in liquids of various fragilities, and provide analytical estimates for the van Hove and self-intermediate scattering functions.
Commentaires: ISI Document Delivery No.: 898IJ Times Cited: 5 Cited Reference Count: 28 English Article 0295-5075
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Direct experimental evidence of a growing length scale accompanying the glass transition
Auteur(s): Berthier L., Biroli G., Bouchaud J.P., Cipelletti L., El masri Djamel, L'Hote D., Ladieu F., Pierno Matteo
(Article) Publié:
Annual Review Of Nuclear And Particle Science, vol. 310 (5755) p.1797-1800 (2005)
Résumé: Understanding glass formation is a challenge, because the existence of a true glass state, distinct from liquid and solid, remains elusive: Glasses are liquids that have become too viscous to flow. An old idea, as yet unproven experimentally, is that the dynamics becomes sluggish as the glass transition approaches, because increasingly larger regions of the material have to move simultaneously to allow flow. We introduce new multipoint dynamical susceptibilities to estimate quantitatively the size of these regions and provide direct experimental evidence that the glass formation of molecular liquids and colloidal suspensions is accompanied by growing dynamic correlation length scales.
Commentaires: ISI Document Delivery No.: 995II Times Cited: 0 Cited Reference Count: 32 English Article
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From gases to glasses in granular matter : Thermodynamic and hydrodynamic aspects
Auteur(s): Berthier L.
Conference: CECAM Workshop (Lyon, FR, 2005-06-27)
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Granular Materials
Auteur(s): Berthier L.
Conference: Granular Materials (, FR, 2005-01-05)
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