1,549 research outputs found
Is the Stillinger and Weber decomposition relevant for coarsening models?
We study three kinetic models with constraint, namely the Symmetrically
Constrained Ising Chain, the Asymmetrically Constrained Ising Chain, and the
Backgammon Model. All these models show glassy behavior and coarsening. We
apply to them the Stillinger and Weber decomposition, and find that they share
the same configurational entropy, despite of their different nonequilibrium
dynamics. We conclude therefore that the Stillinger and Weber decomposition is
not relevant for this type of models.Comment: 14 pages, 12 figure
Inherent Structures, Configurational Entropy and Slow Glassy Dynamics
We give a short introduction to the inherent structure approach, with
particular emphasis on the Stillinger and Weber decomposition, of glassy
systems. We present some of the results obtained in the framework of spin-glass
models and Lennard-Jones glasses. We discuss how to generalize the standard
Stillinger and Weber approach by including the entropy of inherent structures.
Finally we discuss why this approach is probably insufficient to describe the
behavior of some kinetically constrained models.Comment: 16 pages, 8 figures, Contribution to the ESF SPHINX meeting `Glassy
behaviour of kinetically constrained models' (Barcelona, March 22-25, 2001
Heat fluctuations of Brownian oscillators in nonstationary processes: fluctuation theorem and condensation transition
We study analytically the probability distribution of the heat released by an
ensemble of harmonic oscillators to the thermal bath, in the nonequilibrium
relaxation process following a temperature quench. We focus on the asymmetry
properties of the heat distribution in the nonstationary dynamics, in order to
study the forms taken by the Fluctuation Theorem as the number of degrees of
freedom is varied. After analysing in great detail the cases of one and two
oscillators, we consider the limit of a large number of oscillators, where the
behavior of fluctuations is enriched by a condensation transition with a
nontrivial phase diagram, characterized by reentrant behavior. Numerical
simulations confirm our analytical findings. We also discuss and highlight how
concepts borrowed from the study of fluctuations in equilibrium under symmetry
breaking conditions [Gaspard, J. Stat. Mech. P08021 (2012)] turn out to be
quite useful in understanding the deviations from the standard Fluctuation
Theorem.Comment: 16 pages, 7 figure
Broken ergodicity and glassy behavior in a deterministic chaotic map
A network of elements is studied in terms of a deterministic globally
coupled map which can be chaotic. There exists a range of values for the
parameters of the map where the number of different macroscopic configurations
is very large, and there is violation of selfaveraging. The time averages of
functions, which depend on a single element, computed over a time , have
probability distributions that do not collapse to a delta function, for
increasing and . This happens for both chaotic and regular motion, i.e.
positive or negative Lyapunov exponent.Comment: 3 pages RevTeX 3.0, 4 figures included (postscript), files packed
with uufile
Barriers in the p-spin interacting spin-glass model. The dynamical approach
We investigate the barriers separating metastable states in the spherical
p-spin glass model using the instanton method. We show that the problem of
finding the barrier heights can be reduced to the causal two-real-replica
dynamics. We find the probability for the system to escape one of the highest
energy metastable states and the energy barrier corresponding to this process.Comment: 4 pages, 1 figur
The spherical spin glass model: an exactly solvable model for glass to spin-glass transition
We present the full phase diagram of the spherical spin glass model
with . The main outcome is the presence of a new phase with both
properties of Full Replica Symmetry Breaking (FRSB) phases of discrete models,
e.g, the Sherrington-Kirkpatrick model, and those of One Replica Symmetry
Breaking (1RSB). The phase, which separates a 1RSB phase from FRSB phase, is
described by an order parameter function with a continuous part (FRSB)
for and a discontinuous jump (1RSB) at . This phase has a finite
complexity which leads to different dynamic and static properties.Comment: 5 pages, 2 figure
Inherent structures and non-equilibrium dynamics of 1D constrained kinetic models: a comparison study
e discuss the relevance of the Stillinger and Weber approach to the glass
transition investigating the non-equilibrium behavior of models with
non-trivial dynamics, but with simple equilibrium properties. We consider a
family of 1D constrained kinetic models, which interpolates between the
asymmetric chain introduced by Eisinger and J\"ackle [Z. Phys. {\bf B84}, 115
(1991)] and the symmetric chain introduced by Fredrickson and Andersen [Phys.
Rev. Lett {\bf 53}, 1244 (1984)], and the 1D version of the Backgammon model
[Phys. Rev. Lett. {\bf 75}, 1190 (1995)]. We show that the configurational
entropy obtained from the inherent structures is the same for all models
irrespective of their different microscopic dynamics. We present a detailed
study of the coarsening behavior of these models, including the relation
between fluctuations and response. Our results suggest that any approach to the
glass transition inspired by mean-field ideas and resting on the definition of
a configurational entropy must rely on the absence of any growing
characteristic coarsening pattern.Comment: 32 pages, 28 figures, RevTe
Stochastic Resonance in Deterministic Chaotic Systems
We propose a mechanism which produces periodic variations of the degree of
predictability in dynamical systems. It is shown that even in the absence of
noise when the control parameter changes periodically in time, below and above
the threshold for the onset of chaos, stochastic resonance effects appears. As
a result one has an alternation of chaotic and regular, i.e. predictable,
evolutions in an almost periodic way, so that the Lyapunov exponent is positive
but some time correlations do not decay.Comment: 9 Pages + 3 Figures, RevTeX 3.0, sub. J. Phys.
Lack of self-average in weakly disordered one dimensional systems
We introduce a one dimensional disordered Ising model which at zero
temperature is characterized by a non-trivial, non-self-averaging, overlap
probability distribution when the impurity concentration vanishes in the
thermodynamic limit. The form of the distribution can be calculated
analytically for any realization of disorder. For non-zero impurity
concentration the distribution becomes a self-averaging delta function centered
on a value which can be estimated by the product of appropriate transfer
matrices.Comment: 17 pages + 5 figures, TeX dialect: Plain TeX + IOP macros (included
Replica symmetry breaking in long-range glass models without quenched disorder
We discuss mean field theory of glasses without quenched disorder focusing on
the justification of the replica approach to thermodynamics. We emphasize the
assumptions implicit in this method and discuss how they can be verified. The
formalism is applied to the long range Ising model with orthogonal coupling
matrix. We find the one step replica-symmetry breaking solution and show that
it is stable in the intermediate temperature range that includes the glass
state but excludes very low temperatures. At very low temperatures this
solution becomes unstable and this approach fails.Comment: 6 pages, 2 figure
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