82 research outputs found
Fredrickson-Andersen model on Bethe lattice with random pinning
We study the effects of random pinning on the Fredrickson-Andersen model on
the Bethe lattice. We find that the nonergodic transition temperature rises as
the fraction of the pinned spins increases and the transition line terminates
at a critical point. The freezing behavior of the spins is analogous to that of
a randomly pinned p-spin mean-field spin glass model which has been recently
reported. The diverging behavior of correlation lengths in the vicinity of the
terminal critical point is found to be identical to the prediction of the
inhomogeneous mode-coupling theory at the A3 singularity point for the glass
transition.Comment: 6 pages, 7 figure
The Fredrickson-Andersen model with random pinning on Bethe lattices and its MCT transitions
We investigate the dynamics of the randomly pinned Fredrickson-Andersen model
on the Bethe lattice. We find a line of random pinning dynamical transitions
whose dynamical critical properties are in the same universality class of the
and transitions of Mode Coupling Theory. The behavior appears
at the terminal point, where the relaxation becomes logarithmic and the
relaxation time diverges exponentially. We explain the critical behavior in
terms of self-induced disorder and avalanches, strengthening the relationship
discussed in recent works between glassy dynamics and Random Field Ising Model.Comment: 8 pages, 7 figure
Supercooled Liquids Under Shear: Theory and Simulation
We analyze the behavior of supercooled fluids under shear both theoretically
and numerically. Theoretically, we generalize the mode-coupling theory of
supercooled fluids to systems under stationary shear flow. Our starting point
is the set of generalized fluctuating hydrodynamic equations with a convection
term. A nonlinear integro-differential equation for the intermediate scattering
function is constructed. This theory is applied to a two-dimensional colloidal
suspension. The shear rate dependence of the intermediate scattering function
and the shear viscosity is analyzed. We have also performed extensive numerical
simulations of a two-dimensional binary liquid with soft-core interactions
near, but above, the glass transition temperature. Both theoretical and
numerical results show: (i) A drastic reduction of the structural relaxation
time and the shear viscosity due to shear. Both the structural relaxation time
and the viscosity decrease as with an exponent , where is the shear rate. (ii) Almost isotropic dynamics
regardless of the strength of the anisotropic shear flow.Comment: 14 pages, 14 figure
Supercooled liquids under shear: A mode-coupling theory approach
We generalize the mode-coupling theory of supercooled fluids to systems under
stationary shear flow. Our starting point is the generalized fluctuating
hydrodynamic equations with a convection term. The method is applied to a two
dimensional colloidal suspension. The shear rate dependence of the intermediate
scattering function and shear viscosity is analyzed. The results show a drastic
reduction of the structural relaxation time due to shear and strong shear
thinning behavior of the viscosity which are in qualitative agreement with
recent simulations. The microscopic theory with minimal assumptions can explain
the behavior far beyond the linear response regime.Comment: 4 pages, 2 figures, Proceedings to Slow Dynamics in Complex Systems
November3-8, 2003 -- Sendai, Japa
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