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arXiv 1311.7464cond-mat.stat-mech
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粒子与空间扩展环境相互作用的非平衡Langevin方程和有效温度

Nonequilibrium Langevin equation and effective temperature for particle interacting with spatially extended environment

Taiki Haga

摘要:

我们研究了一种新型的Langevin模型,它描述了经典粒子与空间扩展环境相互作用的非平衡动力学。在该模型中,粒子通过非线性相互作用哈密顿量与环境相互作用,在恒定外力的作用下,达到非平凡的非平衡稳态态。我们导出了粒子在非平衡稳态中的有效朗之万方程。利用这个方程,我们计算了有效温度,定义为速度波动的关联函数与相对于小扰动的线性响应函数的比值。结果表明,如果环境的时间尺度和粒子的时间尺度很好地分离,则与粒子的时间尺度相关联的有效温度与动力学温度相同。此外,还导出了动力学温度与驱动力-平均速度曲线曲率之间的关系式。

英文摘要:

We investigate a novel type of Langevin model that describes the nonequilibrium dynamics of a classical particle interacting with a spatially extended environment. In this model, a particle, which interacts with the environment through the nonlinear interaction Hamiltonian, is driven by a constant external force, and subsequently, it reaches a nontrivial nonequilibrium steady state. We derive an effective Langevin equation for the particle in the nonequilibrium steady states. Using this equation, we calculate the effective temperature defined as the ratio of the correlation function of the velocity fluctuation to the linear response function with respect to a small perturbation. As a result, it is shown that the effective temperature associated with the time scale of the particle is identical to the kinetic temperature if the time scale of the environment and that of the particle are well separated. Furthermore, a noteworthy expression, which relates the kinetic temperature with the curvature of the driving force-mean velocity curve, is derived.

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。

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