Lasanta A, Hurtado Pablo I, Prados A
CNR-ISC and Dipartimento di Fisica, Università La Sapienza, p.le A. Moro 2, 00185, Rome, Italy.
Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, 18071, Granada, Spain.
Eur Phys J E Soft Matter. 2016 Mar;39(3):35. doi: 10.1140/epje/i2016-16035-4. Epub 2016 Mar 25.
Understanding the physics of non-equilibrium systems remains one of the major open questions in statistical physics. This problem can be partially handled by investigating macroscopic fluctuations of key magnitudes that characterise the non-equilibrium behaviour of the system of interest; their statistics, associated structures and microscopic origin. During the last years, some new general and powerful methods have appeared to delve into fluctuating behaviour that have drastically changed the way to address this problem in the realm of diffusive systems: macroscopic fluctuation theory (MFT) and a set of advanced computational techniques that make it possible to measure the probability of rare events. Notwithstanding, a satisfactory theory is still lacking in a particular case of intrinsically non-equilibrium systems, namely those in which energy is not conserved but dissipated continuously in the bulk of the system (e.g. granular media). In this work, we put forward the dissipated energy as a relevant quantity in this case and analyse in a pedagogical way its fluctuations, by making use of a suitable generalisation of macroscopic fluctuation theory to driven dissipative media.
理解非平衡系统的物理学仍然是统计物理学中主要的开放性问题之一。通过研究表征感兴趣系统非平衡行为的关键量的宏观涨落，这个问题可以得到部分解决；包括它们的统计特性、相关结构以及微观起源。在过去几年里，出现了一些新的通用且强大的方法来深入研究涨落行为，这些方法极大地改变了在扩散系统领域解决这个问题的方式：宏观涨落理论（MFT）以及一组先进的计算技术，这些技术使得测量罕见事件的概率成为可能。尽管如此，在一类本质上非平衡的系统中，即那些能量不守恒而是在系统主体中持续耗散的系统（例如颗粒介质），仍然缺乏一个令人满意的理论。在这项工作中，我们提出在这种情况下耗散能量是一个相关量，并通过对宏观涨落理论进行适当推广以应用于驱动耗散介质，用一种便于理解教学的方式分析其涨落。
