1,721,031 research outputs found
Asymmetric exclusion processes with constrained dynamics
No full textAsymmetric exclusion processes with locally reversible kinetic constraints are introduced to investigate the effect of nonconservative driving forces in athermal systems. At high density they generally exhibit rheological-like behavior, negative differential resistance, two-step structural relaxation, dynamical heterogeneity and, possibly, a jamming transition driven by the external field
Weakly first-order transition in an athermal lattice gas
No full textWe investigate the phase behavior of a two-dimensional athermal lattice gas in which every hardcore particle can have two or fewer nearest neighboring occupied sites on the square lattice. The ground state and close packing density are determined and it is found that at large chemical potential the model undergoes an ordering phase transition with preferential sub-lattice occupation. Although near the transition point the particle density and entropy exhibit an apparent discontinuity we find that the order parameter and fluctuations of thermodynamic quantities do not scale with the system volume. These paradoxical results are reconciled by analyzing the size dependent flow of the thermal exponent by phenomenological renormalization and the curve-crossing method, which lead to a weakly first-order phase transition scenario
Cooperative heterogeneous facilitation: Multiple glassy states and glass-glass transition
No full textThe formal structure of glass singularities in the mode-coupling theory (MCT) of supercooled liquids dynamics is closely related to that appearing in the analysis of heterogeneous bootstrap percolation on Bethe lattices, random graphs, and complex networks. Starting from this observation one can build up microscopic on-lattice realizations of schematic MCT based on cooperative facilitated spin mixtures. I discuss a microscopic implementation of the F13 schematic model including multiple glassy states and the glass-glass transition. Results suggest that our approach is flexible enough to bridge alternative theoretical descriptions of glassy matter based on the notions of quenched disorder and dynamic facilitation
Effective temperature and compactivity of a lattice gas under gravity
No full textThe notion of longitudinal effective temperature and its relation with the Edwards compactivity are investigated in an abstract lattice gas model of granular material compacting under gravity and weak thermal vibration
Canonical variations on the Kob-Andersen model
No full textVersions of a lattice-gas model with kinetic constraints have been introduced to address some problems in the physics of slowly relaxing systems, such as the nature of the glass transition. the existence of a probability measure underlying the aging dynamics and non-linear transport in the non-equilibrium steady state. A short review of recent progress is given
Crossover from beta- to alpha-relaxation in cooperative facilitation dynamics
No full textalpha and beta relaxation processes are dynamical scaling regimes of glassy systems occurring on two separate
time scales which both diverge as the glass state is approached.We study here the crossover scaling from beta
to alpha relaxation in the cooperative facilitation scenario (CFS) and show that it is quantitatively described,
with no adjustable parameter, by the leading order asymptotic formulas for scaling predicted by the mode-coupling
theory (MCT). These results establish (i) the mutual universality of the MCT and CFS, and (ii) the
existence of a purely dynamic realization of MCT, which is distinct from the well-established random first
order transition scenario for disordered systems. Some implications of the emerging kinetic-static duality
are discussed
Inverse freezing in mean-field models of fragile glasses
No full textA disordered spin model suitable for studying inverse freezing in fragile glass-forming systems is introduced. The model is a microscopic realization of the "random first-order" scenario in which the glass transition can be either continuous or discontinuous in thermodynamic sense. The phase diagram exhibits a first-order transition line between two fluid phases terminating at a critical point. When the interacting degrees of freedom are entropically favored, an inverse static glass transition and a double inverse dynamic freezing appear
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