Dynamic facilitation theory: A statistical mechanics approach to dynamic arrest

Abstract

The modeling of supercooled liquids approaching dynamic arrest has a long tradition, which is documented through a plethora of competing theoretical approaches. Here, we review the modeling of supercooled liquids in terms of dynamic "defects", also called excitations or soft spots, that are able to sustain motion. To this end, we consider a minimal statistical mechanics description in terms of active regions with the order parameter related to their typical size. This is the basis for both Adam-Gibbs and dynamical facilitation theory, which differ in their relaxation mechanism as the liquid is cooled: collective motion of more and more particles vs. concerted hierarchical motion over larger and larger length scales. For the latter, dynamic arrest is possible without a growing static correlation length, and we sketch the derivation of a key result: the parabolic law for the structural relaxation time. We critically discuss claims in favor of a growing static length and argue that the resulting scenarios for pinning and dielectric relaxation are in fact compatible with dynamic facilitation.

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Cited by in corpus (19)

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• The glass transition in molecules, colloids and grains: universality and specificity
• Dynamical coexistence in moderately polydisperse hard-sphere glasses
• Direct numerical analysis of dynamic facilitation in glass-forming liquids
• Sharp threshold for the FA-2f kinetically constrained model
• Exact pre-transition effects in kinetically constrained circuits: dynamical fluctuations in the Floquet-East model
• Boundary conditions dependence of the phase transition in the quantum Newman-Moore model
• Dynamical heterogeneity and large deviations in the open quantum East glass model from tensor networks
• Modeling non-linear dielectric susceptibilities of supercooled molecular liquids
• Exact results on the dynamics of the stochastic Floquet-East model
• Competition between Barrier- and Entropy-Driven Activation in Glasses
• Transmission of mobility via cooperative mechanisms in soft active matter
• Dynamic phase transition induced by active molecules simulating a facilitation mechanism in a supercooled liquid
• Nonlinear dielectric response in glasses: restoring forces and avoided spin-glass criticality
• General Two-Parameter Model of Alpha-Relaxation in Glasses
• Does mesoscopic elasticity control viscous slowing down in glassforming liquids?
• Fredrickson--Andersen model in two dimensions
• Amorphous Order & Non-linear Susceptibilities in Glassy Materials
• A facilitation-induced fluidization transition in supercooled water triggered by a few active molecules