Dipartimento di Fisica, Università di Roma Sapienza, P.le Aldo Moro 2, 00185, Rome, Italy.
Istituto dei Sistemi Complessi-CNR, P.le Aldo Moro 2, 00185, Rome, Italy.
Phys Rev E. 2017 May;95(5-1):052138. doi: 10.1103/PhysRevE.95.052138. Epub 2017 May 23.
We study analytically the probability distribution of the heat released by an ensemble of harmonic oscillators to the thermal bath, in the nonequilibrium relaxation process following a temperature quench. We focus on the asymmetry properties of the heat distribution in the nonstationary dynamics, in order to study the forms taken by the fluctuation theorem as the number of degrees of freedom is varied. After analyzing in great detail the cases of one and two oscillators, we consider the limit of a large number of oscillators, where the behavior of fluctuations is enriched by a condensation transition with a nontrivial phase diagram, characterized by reentrant behavior. Numerical simulations confirm our analytical findings. We also discuss and highlight how concepts borrowed from the study of fluctuations in equilibrium under symmetry-breaking conditions [Gaspard, J. Stat. Mech. (2012) P0802110.1088/1742-5468/2012/08/P08021] turn out to be quite useful in understanding the deviations from the standard fluctuation theorem.
我们分析了在温度淬火后的非平衡弛豫过程中，由一组简谐振荡器向热浴释放的热量的概率分布。我们专注于非定常动力学中热分布的不对称性，以研究波动定理的形式随着自由度数量的变化而变化。在详细分析了一个和两个振荡器的情况后，我们考虑了大量振荡器的极限情况，其中波动的行为通过具有非平凡相图的凝聚相变得到丰富，其特征是重入行为。数值模拟证实了我们的分析结果。我们还讨论并强调了如何从对称性破缺条件下的平衡波动研究中借用的概念[Gaspard, J. Stat. Mech. (2012) P0802110.1088/1742-5468/2012/08/P08021]，这对于理解偏离标准波动定理非常有用。
