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arXiv · 1904.07033

Multiplicative Langevin Equation to Reproduce Long-time Properties of Nonequilibrium Brownian Motion

Atsumasa Seya·Tatsuya Aoyagi·Masato Itami·Yohei Nakayama·Naoko Nakagawa
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Abstract

We statistically examine long time sequences of Brownian motion for a nonequilibrium version of the Rayleigh piston model and confirm that the third cumulant of a long-time displacement for the nonequilibrium Brownian motion linearly increases with the observation time interval. We identify a multiplicative Langevin equation that can reproduce the cumulants of the long-time displacement up to at least the third order, as well as its mean, variance and skewness. The identified Langevin equation involves a velocity-dependent friction coefficient that breaks the time-reversibility and may act as a generator of the directionality. Our method to find the Langevin equation is not specific to the Rayleigh piston model but may be applied to a general time sequence in various fields.

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Atsumasa Seya, Tatsuya Aoyagi, Masato Itami, Yohei Nakayama, Naoko Nakagawa. 2019-04-15. Multiplicative Langevin Equation to Reproduce Long-time Properties of Nonequilibrium Brownian Motion. https://doi.org/10.1088/1742-5468/ab54bc

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