Kwon Chulan, Ao Ping
Department of Physics, Myongji University, Yongin, Gyeonggi-Do 449-728, Republic of Korea.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 Dec;84(6 Pt 1):061106. doi: 10.1103/PhysRevE.84.061106. Epub 2011 Dec 5.
We investigate the properties of the nonequilibrium steady state for the stochastic system driven by a nonlinear drift force and influenced by noises that are not identically and independently distributed. The nonequilibrium steady state (NESS) current results from a residual part of the drift force that is not canceled by the diffusive action of noises. From our previous study for the linear drift force, the NESS current was found to circulate on the equiprobability surface with the maximum at a stable fixed point of the drift force. For the nonlinear drift force, we use the perturbation theory with respect to the cubic and quartic coefficients of the drift force. We find an interesting potential landscape picture where the probability maximum shifts from the fixed point of the drift force and, furthermore, the NESS current has a nontrivial circulation that flows off the equiprobability surface and has various centers not located at the probability maximum. The theoretical result is well confirmed by the computer simulation.
我们研究了由非线性漂移力驱动且受非独立同分布噪声影响的随机系统的非平衡稳态性质。非平衡稳态（NESS）电流源于未被噪声扩散作用抵消的漂移力剩余部分。根据我们之前对线性漂移力的研究，发现NESS电流在等概率面上循环，在漂移力的稳定不动点处达到最大值。对于非线性漂移力，我们使用关于漂移力三次和四次系数的微扰理论。我们发现了一个有趣的势垒景观图，其中概率最大值从漂移力的不动点处发生偏移，此外，NESS电流具有非平凡的循环，其流出等概率面并具有多个不在概率最大值处的中心。理论结果通过计算机模拟得到了很好的证实。
