Chang Hsin, Lee Chi-Lun, Lai Pik-Yin, Chen Yung-Fu
Department of Physics, National Central University, Zhongli 32001, Taiwan.
Phys Rev E. 2021 Feb;103(2-1):022128. doi: 10.1103/PhysRevE.103.022128.
We study the nonequilibrium steady-state (NESS) dynamics of two-dimensional Brownian gyrators under harmonic and nonharmonic potentials via computer simulations and analyses based on the Fokker-Planck equation, while our nonharmonic cases feature a double-well potential and an isotropic quartic potential. In particular, we report two simple methods that can help understand gyrating patterns. For harmonic potentials, we use the Fokker-Planck equation to survey the NESS dynamical characteristics; i.e., the NESS currents gyrate along the equiprobability contours and the stationary point of flow coincides with the potential minimum. As a contrast, the NESS results in our nonharmonic potentials show that these properties are largely absent, as the gyrating patterns are very distinct from those of corresponding probability distributions. Furthermore, we observe a critical case of the double-well potential, where the harmonic contribution to the gyrating pattern becomes absent, and the NESS currents do not circulate about the equiprobability contours near the potential minima even at low temperatures.
我们通过基于福克 - 普朗克方程的计算机模拟和分析，研究了处于谐波势和非谐波势下的二维布朗回转器的非平衡稳态（NESS）动力学，其中我们的非谐波情况具有双阱势和各向同性四次势。特别地，我们报告了两种有助于理解回转模式的简单方法。对于谐波势，我们使用福克 - 普朗克方程来研究NESS动力学特征；即，NESS电流沿等概率轮廓回转，且流动的驻点与势极小值重合。相比之下，我们在非谐波势下的NESS结果表明，这些性质在很大程度上不存在，因为回转模式与相应概率分布的模式非常不同。此外，我们观察到双阱势的一个临界情况，其中对回转模式的谐波贡献消失，并且即使在低温下，NESS电流也不在势极小值附近的等概率轮廓周围循环。
