论文标题

小部分的布朗陀螺仪

Fractional Brownian Gyrator

论文作者

Squarcini, Alessio, Solon, Alexandre, Viot, Pascal, Oshanin, Gleb

论文摘要

当物理系统在恒温下在热浴中演变时,它最终到达了平衡状态,其性质独立于动力学参数和精确的演化情况。对于以平衡驱动的系统而言,这种情况并非如此,相反,该系统具有稳态,其属性取决于动态的完整细节,例如驱动噪声和能量耗散。稳态如何取决于此类参数,通常是一个非平凡的问题。在这里,我们使用二维纳米机器(Brownian Gyrator)的最小模型来解决这个广泛的问题,该模型由由分数高斯噪音驱动的被困粒子组成,该粒子的时间是一个时间,具有长期相关性的噪声家族,并以异常扩散的扩散指数为$α$α$。当噪声在不同的空间方向上有所不同时,我们的分数布朗旋转持续旋转。即使噪声是非平凡的,具有长期的时间相关性,由于其高斯性质,我们也能够通过计算概率密度函数,概率电流,其卷曲速度和角度速度并通过数值结果来分析产生的非平衡稳态表征。

When a physical system evolves in a thermal bath at a constant temperature, it arrives eventually to an equilibrium state whose properties are independent of the kinetic parameters and of the precise evolution scenario. This is generically not the case for a system driven out of equilibrium which, on the contrary, reaches a steady-state with properties that depend on the full details of the dynamics such as the driving noise and the energy dissipation. How the steady state depends on such parameters is in general a non-trivial question. Here, we approach this broad problem using a minimal model of a two-dimensional nano-machine, the Brownian gyrator, that consists of a trapped particle driven by fractional Gaussian noises -- a family of noises with long-ranged correlations in time and characterized by an anomalous diffusion exponent $α$. When the noise is different in the different spatial directions, our fractional Brownian gyrator persistently rotates. Even if the noise is non-trivial, with long-ranged time correlations, thanks to its Gaussian nature we are able to characterize analytically the resulting nonequilibrium steady state by computing the probability density function, the probability current, its curl and the angular velocity and complement our study by numerical results.

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