Non-Gaussianity of the van Hove function and dynamic-heterogeneity length scale
| Autor: | Indrajit Tah, Smarajit Karmakar, Bhanu Prasad Bhowmik |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
Length scale Scale (ratio) Statistical Mechanics (cond-mat.stat-mech) Gaussian FOS: Physical sciences 02 engineering and technology Function (mathematics) Disordered Systems and Neural Networks (cond-mat.dis-nn) Condensed Matter - Disordered Systems and Neural Networks Condensed Matter - Soft Condensed Matter 021001 nanoscience & nanotechnology 01 natural sciences Exponential function symbols.namesake Distribution function Non-Gaussianity 0103 physical sciences symbols Probability distribution Soft Condensed Matter (cond-mat.soft) Statistical physics 010306 general physics 0210 nano-technology Condensed Matter - Statistical Mechanics |
| Zdroj: | Physical review. E. 98(2-1) |
| ISSN: | 2470-0053 |
| Popis: | Non-Gaussian nature of the probability distribution of particles' displacements in the supercooled temperature regime in glass-forming liquids are believed to be one of the major hallmarks of glass transition. It has already been established that this probability distribution, which is also known as the van Hove function, shows universal exponential tail. The origin of such an exponential tail in the distribution function is attributed to the hopping motion of particles observed in the supercooled regime. The non-Gaussian nature can also be explained if one assumes that the system has heterogeneous dynamics in space and time. Thus exponential tail is the manifestation of dynamic heterogeneity. In this work we directly show that non-Gaussianity of the distribution of particles' displacements occur over the dynamic heterogeneity length scale and the dynamical behavior course grained over this length scale becomes homogeneous. We study the non-Gaussianity of the van Hove function by systematically coarse graining at different length scales and extract the length scale of dynamic heterogeneity at which the shape of the van Hove function crosses over from non-Gaussian to Gaussian. The obtained dynamic heterogeneity scale is found to be in very good agreement with the scale obtained from other conventional methods. |
| Databáze: | OpenAIRE |
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