2023-10-11 スイス連邦工科大学ローザンヌ校(EPFL)
◆研究者は、ダイナミカル相関長の成長を説明する「スケーリング理論」を開発し、これによって熱的なアバランチなどの現象も説明されました。この研究は、ガラスのダイナミクスを理解し、他の複雑なシステムにも応用できる可能性を示唆しています。
＜関連情報＞
- https://actu.epfl.ch/news/unraveling-the-mysteries-of-glassy-liquids/
- https://journals.aps.org/prx/abstract/10.1103/PhysRevX.13.031034#fulltext
ガラス形成液体における動的不均一性と緩和のアバランシェのスケーリング記述 Scaling Description of Dynamical Heterogeneity and Avalanches of Relaxation in Glass-Forming Liquids
Ali Tahaei, Giulio Biroli, Misaki Ozawa, Marko Popović, and Matthieu Wyart
Physical Review X Published 21 September 2023
DOI:https://doi.org/10.1103/PhysRevX.13.031034
ABSTRACT
We provide a theoretical description of dynamical heterogeneities in glass-forming liquids, based on the premise that relaxation occurs via local rearrangements coupled by elasticity. In our framework, the growth of the dynamical correlation length ξ and of the correlation volume χ4 are controlled by a zero-temperature fixed point. We connect this critical behavior to the properties of the distribution of local energy barriers at zero temperature. Our description makes a direct connection between dynamical heterogeneities and avalanche-type relaxation associated to dynamic facilitation, allowing us to relate the size distribution of heterogeneities to their time evolution. Within an avalanche, a local region relaxes multiple times; the more, the larger the avalanche. This property, related to the nature of the zero-temperature fixed point, directly leads to decoupling of particle diffusion and relaxation time (the so-called Stokes-Einstein violation). Our most salient predictions are tested and confirmed by numerical simulations of scalar and tensorial thermal elastoplastic models. Our most salient predictions are tested and confirmed by numerical simulations of scalar and tensorial thermal elasto-plastic models, and in agreement with molecular dynamic simulations.
