Rattling news!
"... This goal is the motivation behind a recently introduced principle of physics called rattling, which posits that systems with sufficiently "messy" dynamics organize into what researchers refer to as low rattling states. ...
how rattling is related to the amount of time that a system spends in a state. Their theory further identifies the classes of systems for which rattling explains self-organization. ..."
From the significance and abstract:
"Significance
Fundamentals of statistical physics explain that systems in thermal equilibrium exhibit spontaneous order because orderly configurations have low energy. This fact is remarkable, and powerful, because energy is a “local” property of configurations. Nonequilibrium systems, including engineered and living systems, can also exhibit order, but there is no property analogous to energy that generally explains why orderly configurations of these systems often emerge. However, recent experiments suggest that a local property called “rattling” predicts which configurations are favored, at least for a broad class of nonequilibrium systems. We develop a theory of rattling that explains for which systems it works and why, and we demonstrate its application across scientific domains.
Abstract
The global steady state of a system in thermal equilibrium exponentially favors configurations with lesser energy. This principle is a powerful explanation of self-organization because energy is a local property of configurations. For nonequilibrium systems, there is no such property for which an analogous principle holds, hence no common explanation of the diverse forms of self-organization they exhibit. However, a flurry of recent empirical results has shown that a local property of configurations called “rattling” predicts the steady states of some nonequilibrium systems, leading to claims of a far-reaching principle of nonequilibrium self-organization. But for which nonequilibrium systems is rattling accurate, and why? We develop a theory of rattling in terms of Markov processes that gives simple and precise answers to these key questions. Our results show that rattling predicts a broader class of nonequilibrium steady states than has been claimed and for different reasons than have been suggested. Its predictions hold to an extent determined by the relative variance of, and correlation between, the local and global “parts” of a steady state. We show how these quantities characterize the local-global relationships of various random walks on random graphs, spin-glass dynamics, and models of animal collective behavior. Surprisingly, we find that the core idea of rattling is so general as to apply to equilibrium and nonequilibrium systems alike."
Rattling Physics with New Math (original news release)
A local–global principle for nonequilibrium steady states (no public access)
Professor Dana Randall
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