A classical particle system coupled with a thermostat driven by an external constant force reaches its steady state when the ensemble-averaged drift velocity does not vary with time. The statistical mechanics of such a system is derived merely based on the equal probability and ergodicity principles, free from any conclusions drawn on equilibrium statistical mechanics or local equilibrium hypothesis. The momentum space distribution is determined by a random walk argument, and the position space distribution is determined by employing the equal probability and ergodicity principles. The expressions for energy, entropy, free energy, and pressures are then deduced, and the relation among external force, drift velocity, and temperature is also established. Moreover, the relaxation towards its equilibrium is found to be an exponentially decaying process obeying the minimum entropy production theorem.

中文翻译：

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由恒定外力驱动的非平衡稳态经典粒子系统的统计力学

当整体平均漂移速度不随时间变化时，经典粒子系统与由外部恒定力驱动的恒温器相结合，达到其稳态。这种系统的统计力学只是基于等概率和遍历性原理推导出来的，没有根据均衡统计力学或局部均衡假设得出的任何结论。动量空间分布由随机游走参数确定，位置空间分布由等概率和遍历原则确定。然后推导出能量、熵、自由能和压力的表达式，并建立外力、漂移速度和温度之间的关系。而且，