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arXiv · 1905.06796

Non-equilibrium probability flux of a thermally driven micromachine

Isamu Sou·Yuto Hosaka·Kento Yasuda·Shigeyuki Komura
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Abstract

We discuss the non-equilibrium statistical mechanics of a thermally driven micromachine consisting of three spheres and two harmonic springs [Y. Hosaka et al., J. Phys. Soc. Jpn. 86, 113801 (2017)]. We obtain the non-equilibrium steady state probability distribution function of such a micromachine and calculate its probability flux in the corresponding configuration space. The resulting probability flux can be expressed in terms of a frequency matrix that is used to distinguish between a non-equilibrium steady state and a thermal equilibrium state satisfying detailed balance. The frequency matrix is shown to be proportional to the temperature difference between the spheres. We obtain a linear relation between the eigenvalue of the frequency matrix and the average velocity of a thermally driven micromachine that can undergo a directed motion in a viscous fluid. This relation is consistent with the scallop theorem for a deterministic three-sphere microswimmer.

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Isamu Sou, Yuto Hosaka, Kento Yasuda, Shigeyuki Komura. 2019-05-16. Non-equilibrium probability flux of a thermally driven micromachine. https://doi.org/10.1103/physreve.100.022607

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