We study far from equilibrium transport of a periodically driven inertialBrownian particle moving in a periodic potential. As detected recently for aSQUID ratchet dynamics (Spiechowicz J. & Luczka J. Phys. Rev. E 91, 062104(2015)), the mean square deviation of the particle position from its averagemay involve three distinct intermediate, although extended diffusive regimes:initially as superdiffusion, followed by subdiffusion and finally, normaldiffusion in the asymptotic long time limit. Even though these anomalies aretransient effects, their lifetime can be many, many orders of magnitude longerthan the characteristic time scale of the setup and turns out to beextraordinarily sensitive to the system parameters like temperature or thepotential asymmetry. In the paper we reveal mechanisms of diffusion anomaliesrelated to ergodicity of the system, symmetry breaking of the periodicpotential and ultraslow relaxation of the particle velocity towards its steadystate. Similar sequences of the diffusive behaviours could be detected invarious systems including, among others, colloidal particles in randompotentials, glass forming liquids and granular gases.
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机译:我们研究的不是周期性驱动的惯性布朗粒子在周期性电势中的平衡输运。正如最近针对aSQUID棘轮动力学所检测到的那样(Spiechowicz J.&Luczka J. Phys。Rev. E 91,062104(2015)),粒子位置与其平均值的均方差可能涉及三个不同的中间产物,尽管扩展了扩散机制:先是超扩散,然后是亚扩散,最后是渐近长时限内的正常扩散。即使这些异常是短暂的影响,它们的寿命也可能比设置的特征时间标度长很多很多数量级,并且对诸如温度或电位不对称之类的系统参数异常敏感。在本文中,我们揭示了与系统遍历性有关的扩散异常机制,周期势的对称破坏和粒子速度向稳态的超慢弛豫。可以在各种系统中检测到相似的扩散行为序列,其中包括随机电位中的胶体颗粒,玻璃形成液体和颗粒气体。
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