Max-Planck-Institute for Dynamics and Self-Organization, Am Fassberg 17, 37073 Göttingen, Germany.
Soft Matter. 2017 Feb 7;13(5):898-910. doi: 10.1039/c6sm02224c. Epub 2017 Jan 19.
The emergence of patterns and phase separation in many-body systems far from thermal equilibrium is discussed using the example of driven granular gases. It is shown that phase separation follows a similar mechanism as in the systems of active Brownian particles. Depending on the quantities chosen for observation, it may or may not be easy to find functionals analogous to the free energy in equilibrium statistical physics. We argue that although such functionals can always be derived from the dynamics, it is of only limited value for predicting relevant aspects of the nonequilibrium steady state of the system. Consequently, although there is indeed a 'principle' governing the selection of collective nonequilibrium steady states (and the corresponding large deviation functional can be identified), it is not generally useful for predicting the behaviour of the system.
本文以驱动的颗粒气体为例，讨论了远离热平衡的多体系统中模式和相分离的出现。结果表明，相分离遵循与活性布朗粒子系统类似的机制。根据选择的观测量，可能很容易找到类似于平衡统计物理中自由能的泛函，也可能不容易找到。我们认为，尽管这样的泛函总是可以从动力学中导出，但对于预测系统非平衡定态的相关方面，其价值是有限的。因此，尽管确实存在一个“原则”来支配集体非平衡定态的选择（并且可以识别相应的大偏差泛函），但它通常并不用于预测系统的行为。
