3 research outputs found
Scaling and super-universality in the coarsening dynamics of the 3d random field Ising model
We study the coarsening dynamics of the three-dimensional random field Ising
model using Monte Carlo numerical simulations. We test the dynamic scaling and
super-scaling properties of global and local two-time observables. We treat in
parallel the three-dimensional Edward-Anderson spin-glass and we recall results
on Lennard-Jones mixtures and colloidal suspensions to highlight the common and
different out of equilibrium properties of these glassy systems.Comment: 18 pages, 21 figure
Growing dynamical length, scaling and heterogeneities in the 3d Edwards-Anderson model
We study numerically spatio-temporal fluctuations during the
out-of-equilibrium relaxation of the three-dimensional Edwards-Anderson model.
We focus on two issues. (1) The evolution of a growing dynamical length scale
in the glassy phase of the model, and the consequent collapse of the
distribution of local coarse-grained correlations measured at different pairs
of times on a single function using {\it two} scaling parameters, the value of
the global correlation at the measuring times and the ratio of the coarse
graining length to the dynamical length scale (in the thermodynamic limit). (2)
The `triangular' relation between coarse-grained local correlations at three
pairs of times taken from the ordered instants .
Property (1) is consistent with the conjecture that the development of
time-reparametrization invariance asymptotically is responsible for the main
dynamic fluctuations in aging glassy systems as well as with other mechanisms
proposed in the literature. Property (2), we stress, is a much stronger test of
the relevance of the time-reparametrization invariance scenario.Comment: 24 pages, 12 fig
Growth of a dynamical correlation length in an aging superspin glass
We report on zero field cooled magnetization relaxation experiments on a
concen- trated frozen ferrofluid exhibiting a low temperature superspin glass
transition. With a method initially developed for spin glasses, we investigate
the field dependence of the relaxations that take place after different aging
times. We extract the typical number of correlated spins involved in the aging
dynamics. This brings important insights into the dynamical correlation length
and its time growth. Our results, consistent with expressions obtained for spin
glasses, extend the generality of these behaviours to the class of superspin
glasses. Since the typical flipping time is much larger for superspins than for
atomic spins, our experiments probe a time regime much closer to that of
numerical simulations