Connecting microscopic simulations with kinetically constrained models of glasses

Downton, Matthew T.; Kennett, Malcolm P.

doi:10.1103/physreve.76.031502

Cited by 8 publications

(3 citation statements)

References 70 publications

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“…4, we see this property emerges from Newtonian dynamics of a sufficiently supercooled or compressed material. A few published papers have focused on how facilitation can be an emergent property [104,105,106,107,108,109]. The surging events described in the previous subsection coincide with the geometry of excitations in the KCM known as the "East" model [38]; see, in particular, Figs.…”

Section: B Excitation Lines Decoupling and Continuous-time Random Walksmentioning

confidence: 82%

Dynamics on the Way to Forming Glass: Bubbles in Space-Time

Chandler

Garrahan

2010

Annu. Rev. Phys. Chem.

477

585

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We review a theoretical perspective of the dynamics of glass-forming liquids and the glass transition, a perspective developed during this past decade based on the structure of trajectory space. This structure emerges from spatial correlations of dynamics that appear in disordered systems as they approach nonergodic or jammed states. It is characterized in terms of dynamical heterogeneity, facilitation, and excitation lines. These features are associated with a newly discovered class of nonequilibrium phase transitions. Equilibrium properties have little, if anything, to do with it. The broken symmetries of these transitions are obscure or absent in spatial structures, but they are vivid in space-time (i.e., trajectory space). In our view, the glass transition is an example of this class of transitions. The basic ideas and principles we review were originally developed through the analysis of idealized and abstract models. Nevertheless, the central ideas are easily illustrated with reference to molecular dynamics of more realistic atomistic models, and we use that illustrative approach here.

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Section: B Excitation Lines Decoupling and Continuous-time Random Walksmentioning

confidence: 82%

Dynamics on the Way to Forming Glass: Bubbles in Space-Time

Chandler

Garrahan

2010

Annu. Rev. Phys. Chem.

477

585

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“…A central criticism about the free volume approach, that is equally relevant for KCMs, concerns the identification, at the molecular level, of the vacancies (in lattice gases), mobility defects (in spin facilitated models), or of the free volume itself. The attempts to provide reasonable coarse-graining from molecular models with continuous degrees of freedom to lattice models with kinetic rules have been, for a very long time, quite limited and not fully convincing [144,262].…”

Section: Defects: Connection With Hamiltonian Dynamics Modelsmentioning

confidence: 99%

Glasses and aging: A Statistical Mechanics Perspective

Arceri¹,

Landes²,

Biroli³

2020

Preprint

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CONTENTS I. Glossary 1 II. Definition of the subject 2 III. Phenomenology 3 A. Basic facts 3 B. Static and dynamic correlation functions 5 References 42 I. GLOSSARYWe start with a few concise definitions of the most important concepts discussed in this article.Glass transition-For molecular liquids, the glass transition denotes a crossover from a viscous liquid to an amorphous solid. Experimentally, the crossover takes place at the glass temperature, T g , conventionally defined as the temperature where the liquid's viscosity reaches the arbitrary value of 10 12 Pa.s. The glass transition

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“…These models are generally understood as an effective model for some coarse-grained degree of freedom (often referred to as spins), and at low temperatures, the dynamics can be understood as a few up-spins or "defects" in a background sea of down spins [34]. We have recently attempted to provide a coarse-graining procedure to map the dynamics of a glass-former onto a KCM, using local mean squared displacement as a means to define spins [35]. This approach found kinetically constrained behaviour became increasingly important at low temperatures, but only on timescales longer than the alpha relaxation time, whereas one would hope that the alpha relaxation time was in fact a consequence of the KCM, rather than an input.…”

Section: Introductionmentioning

confidence: 99%

Following microscopic motion in a two-dimensional glass-forming binary fluid

Downton

Kennett

2008

J. Phys.: Condens. Matter

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The dynamics of a binary mixture of large and small discs are studied at temperatures approaching the glass transition using an analysis based on the topology of the Voronoi polygon surrounding each atom. At higher temperatures we find that dynamics is dominated by fluid-like motion that involves particles entering and exiting the nearest-neighbour shells of nearby particles. As the temperature is lowered, the rate of topological moves decreases and motion becomes localised to regions of mixed pentagons and heptagons. In addition we find that in the low temperature state particles may translate significant distances without undergoing changes in their nearest neighbour shell. These results have implications for dynamical heterogeneities in glass forming liquids.

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Connecting microscopic simulations with kinetically constrained models of glasses

Cited by 8 publications

References 70 publications

Dynamics on the Way to Forming Glass: Bubbles in Space-Time

Dynamics on the Way to Forming Glass: Bubbles in Space-Time

Glasses and aging: A Statistical Mechanics Perspective

Following microscopic motion in a two-dimensional glass-forming binary fluid

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