10 research outputs found
From particles to spins: Eulerian formulation of supercooled liquids and glasses
The dynamics of supercooled liquid and glassy systems are usually studied within the Lagrangian representation, in which the positions and velocities of distinguishable interacting particles are followed. Within this representation, however, it is difficult to define measures of spatial heterogeneities in the dynamics, as particles move in and out of any one given region within long enough times. It is also nontransparent how to make connections between the structural glass and the spin glass problems within the Lagrangian formulation. We propose an Eulerian formulation of supercooled liquids and glasses that allows for a simple connection between particle and spin systems, and that permits the study of dynamical heterogeneities within a fixed frame of reference similar to the one used for spin glasses. We apply this framework to the study of the dynamics of colloidal particle suspensions for packing fractions corresponding to the supercooled and glassy regimes, which are probed via confocal microscopy.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta
From particles to spins: Eulerian formulation of supercooled liquids and glasses
The dynamics of supercooled liquid and glassy systems are usually studied within the Lagrangian representation, in which the positions and velocities of distinguishable interacting particles are followed. Within this representation, however, it is difficult to define measures of spatial heterogeneities in the dynamics, as particles move in and out of any one given region within long enough times. It is also nontransparent how to make connections between the structural glass and the spin glass problems within the Lagrangian formulation. We propose an Eulerian formulation of supercooled liquids and glasses that allows for a simple connection between particle and spin systems, and that permits the study of dynamical heterogeneities within a fixed frame of reference similar to the one used for spin glasses. We apply this framework to the study of the dynamics of colloidal particle suspensions for packing fractions corresponding to the supercooled and glassy regimes, which are probed via confocal microscopy.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta
From particles to spins: Eulerian formulation of supercooled liquids and glasses
The dynamics of supercooled liquid and glassy systems are usually studied
within the Lagrangian representation, in which the positions and velocities of
distinguishable interacting particles are followed. Within this representation,
however, it is difficult to define measures of spatial heterogeneities in the
dynamics, as particles move in and out of any one given region within long
enough times. It is also non-transparent how to make connections between the
structural glass and the spin glass problems within the Lagrangian formulation.
We propose an Eulerian formulation of supercooled liquids and glasses that
allows for a simple connection between particle and spin systems, and that
permits the study of dynamical heterogeneities within a fixed frame of
reference similar to the one used for spin glasses. We apply this framework to
the study of the dynamics of colloidal particle suspensions for packing
fractions corresponding to the supercooled and glassy regimes, which are probed
via confocal microscopy.Comment: 7 pages, 7 figure
Reply to ``Comment on `Hole-burning experiments within glassy models with infinite range interactions' ''
This is a reply to the comments by Richter and Chamberlin, and Diezemann and
Bohmer to our paper (Phys. Rev. Lett. 85, 3448 (2000)). As further evidence for
the claims in this Letter, we here reproduce the nonlinear spectral
hole-burning experimental protocol in an equilibrated fully connected
spin-glass model and we exhibit frequency selectivity, together with a shift in
the base of the spectral hole.Comment: 1 page, two figures, to appear in Phys. Rev. Let
From particles to spins: Eulerian formulation of supercooled liquids and glasses
The dynamics of supercooled liquid and glassy systems are usually studied within the Lagrangian representation, in which the positions and velocities of distinguishable interacting particles are followed. Within this representation, however, it is difficult to define measures of spatial heterogeneities in the dynamics, as particles move in and out of any one given region within long enough times. It is also nontransparent how to make connections between the structural glass and the spin glass problems within the Lagrangian formulation. We propose an Eulerian formulation of supercooled liquids and glasses that allows for a simple connection between particle and spin systems, and that permits the study of dynamical heterogeneities within a fixed frame of reference similar to the one used for spin glasses. We apply this framework to the study of the dynamics of colloidal particle suspensions for packing fractions corresponding to the supercooled and glassy regimes, which are probed via confocal microscopy.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta
Growing correlations and aging of an elastic line in a random potential
We study the thermally assisted relaxation of a directed elastic line in a
two dimensional quenched random potential by solving numerically the
Edwards-Wilkinson equation and the Monte Carlo dynamics of a solid-on-solid
lattice model. We show that the aging dynamics is governed by a growing
correlation length displaying two regimes: an initial thermally dominated
power-law growth which crosses over, at a static temperature-dependent
correlation length , to a logarithmic growth consistent with an
algebraic growth of barriers. We present a scaling arguments to deal with the
crossover-induced geometrical and dynamical effects. This analysis allows to
explain why the results of most numerical studies so far have been described
with effective power-laws and also permits to determine the observed anomalous
temperature-dependence of the characteristic growth exponents. We argue that a
similar mechanism should be at work in other disordered systems. We generalize
the Family-Vicsek stationary scaling law to describe the roughness by
incorporating the waiting-time dependence or age of the initial configuration.
The analysis of the two-time linear response and correlation functions shows
that a well-defined effective temperature exists in the power-law regime.
Finally, we discuss the relevance of our results for the slow dynamics of
vortex glasses in High-Tc superconductors.Comment: 18 pages, 15 figures, submitted for publicatio
Hole-burning experiments within solvable glassy models
We reproduce the results of non-resonant spectral hole-burning experiments
with fully-connected (equivalently infinite-dimensional) glassy models that are
generalizations of the mode-coupling approach to nonequilibrium situations. We
show that an ac-field modifies the integrated linear response and the
correlation function in a way that depends on the amplitude and frequency of
the pumping field. We study the effect of the waiting and recovery-times and
the number of oscillations applied. This calculation will help descriminating
which results can and which cannot be attributed to dynamic heterogeneities in
real systems.Comment: 4 pages, 8 figures, RevTe
Out-of-equilibrium relaxation of the Edwards-Wilkinson elastic line
We study the non-equilibrium relaxation of an elastic line described by the
Edwards-Wilkinson equation. Although this model is the simplest representation
of interface dynamics, we highlight that many (not though all) important
aspects of the non-equilibrium relaxation of elastic manifolds are already
present in such quadratic and clean systems. We analyze in detail the aging
behaviour of several two-times averaged and fluctuating observables taking into
account finite-size effects and the crossover to the stationary and equilibrium
regimes. We start by investigating the structure factor and extracting from its
decay a growing correlation length. We present the full two-times and size
dependence of the interface roughness and we generalize the Family-Vicsek
scaling form to non-equilibrium situations. We compute the incoherent cattering
function and we compare it to the one measured in other glassy systems. We
analyse the response functions, the violation of the fluctuation-dissipation
theorem in the aging regime, and its crossover to the equilibrium relation in
the stationary regime. Finally, we study the out-of-equilibrium fluctuations of
the previously studied two-times functions and we characterize the scaling
properties of their probability distribution functions. Our results allow us to
obtain new insights into other glassy problems such as the aging behavior in
colloidal glasses and vortex glasses.Comment: 33 pages, 16 fig
Spatially heterogeneous ages in glassy dynamics
We construct a framework for the study of fluctuations in the nonequilibrium
relaxation of glassy systems with and without quenched disorder. We study two
types of two-time local correlators with the aim of characterizing the
heterogeneous evolution: in one case we average the local correlators over
histories of the thermal noise, in the other case we simply coarse-grain the
local correlators. We explain why the former describe the fingerprint of
quenched disorder when it exists, while the latter are linked to noise-induced
mesoscopic fluctuations. We predict constraints on the pdfs of the fluctuations
of the coarse-grained quantities. We show that locally defined correlations and
responses are connected by a generalized local out-of-equilibrium
fluctuation-dissipation relation. We argue that large-size heterogeneities in
the age of the system survive in the long-time limit. The invariance of the
theory under reparametrizations of time underlies these results. We relate the
pdfs of local coarse-grained quantities and the theory of dynamic random
manifolds. We define a two-time dependent correlation length from the spatial
decay of the fluctuations in the two-time local functions. We present numerical
tests performed on disordered spin models in finite and infinite dimensions.
Finally, we explain how these ideas can be applied to the analysis of the
dynamics of other glassy systems that can be either spin models without
disorder or atomic and molecular glassy systems.Comment: 47 pages, 60 Fig