Accueil >
Production scientifique
(327) Production(s) de BERTHIER L.
|
Dynamic criticality in glass forming liquids
Auteur(s): Berthier L.
(Séminaires)
University of Nottingham, School of Physics and astronomy (Nottingham, UK, FR), 2004-00-00 |
|
A few bubbles in a glass
Auteur(s): Berthier L.
Conférence invité: Fluctuations and Noise 2004 (Maspalomas, Gran Canaria Island, Spain, FR, 2004-05-25)
Actes de conférence: Spie, vol. 5469 p.177 (2004)
|
|
|
Shear localization in a model glass
Auteur(s): Varnik F., Bocquet L., Barrat J.L., Berthier L.
(Article) Publié:
Physical Review Letters, vol. 90 p.095702 (2003)
Résumé: Using molecular dynamics simulations, we show that a simple model of a glassy material exhibits the shear localization phenomenon observed in many complex fluids. At low shear rates, the system separates into a fluidized shear band and an unsheared part. The two bands are characterized by a very different dynamics probed by a local intermediate scattering function. Furthermore, a stick-slip motion is observed at very small shear rates. Our results, which open the possibility of exploring complex rheological behavior using simulations, are compared to recent experiments on various soft glasses.
Commentaires: English Article 653NU
|
|
|
Comment on Fluctuation-dissipation relations in the nonequilibrium critical dynamics of Ising models
Auteur(s): Mayer P., Berthier L., Garrahan J.P., Sollich P.
(Article) Publié:
Physical Review E: Statistical, Nonlinear, And Soft Matter Physics, vol. 70 p.018102 (2004)
Résumé: We have recently shown that in nonequilibrium spin systems at criticality the limit X-infinity of the fluctuation-dissipation ratio X(t,t(w)) for tt(w)1 can be measured using observables such as magnetization or energy [ Phys. Rev. E 68, 016116 (2003) ]. Pleimling argues in a Comment [preceding paper, Phys. Rev. 70, 018101 (2004) ] on our paper that for such observables correlation and response functions are dominated by one-time quantities dependent only on t, and are therefore not suitable for a determination of X-infinity. Using standard scaling forms of correlation and response functions, as used by Pleimling, we show that our data do have a genuine two-time dependence and allow X(t,t(w)) and X-infinity to be measured, so that Pleimling's criticisms are easily refuted. We also compare with predictions from renormalization-group calculations, which are consistent with our numerical observation of a fluctuation-dissipation plot for the magnetization that is very close to a straight line. A key point remains that coherent observables make measurements of X-infinity easier than the traditionally used incoherent ones, producing fluctuation-dissipation plots whose slope is close to X-infinity over a much larger range.
Commentaires: English Letter Part 2 844CV
|
|
Dynamic heterogeneities, defects, and the non-topographic view of glass transition phenomena
Auteur(s): Garrahan J.P., Berthier L.
(Article) Publié:
Abstracts Of Papers Of The American Chemical Society, vol. 226 p.U278-U278 (2003)
|
|
|
Energetics of clusters in the two-dimensional Gaussian Ising spin glass
Auteur(s): Berthier L., Young A.P.
(Article) Publié:
Journal Of Physics A: Mathematical And General, vol. 36 p.10835-10846 (2003)
Résumé: We study numerically the properties of local low-energy excitations in the two-dimensional Ising spin glass with Gaussian couplings. Given the ground state, we determine the lowest-lying connected cluster of flipped spins containing one given spin, either with a fixed volume, or with a volume constrained to lie in a certain range. Our aim is to understand corrections to the scaling predicted by the droplet picture of spin glasses and to resolve contradictory results reported in the literature for the stiffness exponent. We find no clear trace of corrections to scaling, and the obtained stiffness exponent is in relatively good agreement with standard domain-wall calculations.
Commentaires: English Article 747BX
|
|
|
Real space origin of temperature crossovers in supercooled liquids
Auteur(s): Berthier L., Garrahan J.P.
(Article) Publié:
Physical Review E: Statistical, Nonlinear, And Soft Matter Physics, vol. 68 p.041201 (2003)
Résumé: We show that the various crossovers between dynamical regimes observed in experiments and simulations of supercooled liquids can be explained in simple terms from the existence and statistical properties of dynamical heterogeneities. We confirm that dynamic heterogeneity is responsible for the slowing down of glass formers at temperatures well above the dynamic singularity T-c predicted by mode-coupling theory. Our results imply that activated processes govern the long-time dynamics even in the temperature regime where they are neglected by mode-coupling theory. We show that alternative interpretations based on topographic properties of the potential energy landscape are inefficient ways of describing simple physical features which are naturally accounted for within our approach. We show in particular that the reported links between mode coupling and landscape singularities do not exist.
Commentaires: English Article Part 1 743JR
|