arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0710.3673cond-mat.stat-mech
收藏

Nose-Hoover边界恒温系统的涨落关系

On the Fluctuation Relation for Nose-Hoover Boundary Thermostated Systems

Carlos Mejia-Monasterio, Lamberto Rondoni

摘要:

本文讨论了在不同温度下与两个确定性恒温器接触的力学系统的瞬态和稳态涨落关系。该系统是一个修改的洛伦兹气体中的固定散射体与气体的粒子交换能量,和恒温器是由两个Nosé-胡佛恒温器应用在系统的边界模拟。瞬态波动关系,它只适用于一个精确的选择初始合奏,验证在任何时候,正如预期的那样。如果考虑不同的初始系综,则需要比局部平衡所需的介观尺度更长的时间。这表明,如在我们的系统中明确检查的,当[D.J.Searles,{\em et al.},J. Stat. Phys.128,1337(2007)]中的方法,验证了稳态涨落关系的有效性。对于稳态波动的相空间收缩率$\zL$和耗散函数$\zW$,一个类似的松弛制度在较短的平均时间被发现。量$\zW$满足良好的精度波动关系的时间大于介观时间尺度;量$\zL$出现后开始单调收敛。这与$\zW$和$\zL$相差一个总时间导数,以及$\zL$的概率分布函数的尾部是高斯分布的事实是一致的。

英文摘要:

We discuss the transient and steady state fluctuation relation for a mechanical system in contact with two deterministic thermostats at different temperatures. The system is a modified Lorentz gas in which the fixed scatterers exchange energy with the gas of particles, and the thermostats are modelled by two Nosé-Hoover thermostats applied at the boundaries of the system. The transient fluctuation relation, which holds only for a precise choice of the initial ensemble, is verified at all times, as expected. Times longer than the mesoscopic scale, needed for local equilibrium to be settled, are required if a different initial ensemble is considered. This shows how the transient fluctuation relation asymptotically leads to the steady state relation when, as explicitly checked in our systems, the condition found in [D.J. Searles, {\em et al.}, J. Stat. Phys. 128, 1337 (2007)], for the validity of the steady state fluctuation relation, is verified. For the steady state fluctuations of the phase space contraction rate $\zL$ and of the dissipation function $\zW$, a similar relaxation regime at shorter averaging times is found. The quantity $\zW$ satisfies with good accuracy the fluctuation relation for times larger than the mesoscopic time scale; the quantity $\zL$ appears to begin a monotonic convergence after such times. This is consistent with the fact that $\zW$ and $\zL$ differ by a total time derivative, and that the tails of the probability distribution function of $\zL$ are Gaussian.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑