Nonequilibrium probability flux of a thermally driven micromachine

Sou, Isamu; Hosaka, Yuto; Yasuda, Katsutaro; Komura, Shigeyuki

doi:10.1103/physreve.100.022607

Cited by 27 publications

(33 citation statements)

References 41 publications

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“…The competition between the swimmer size and the characteristic length scale associated with the fluid internal structure gives rise to the rich dynamics [21,22]. The present authors have also proposed a generalized three-sphere microswimmer model in which the spheres are connected by two harmonic springs, i.e., an elastic microswimmer [23][24][25][26]. It has been shown that an elastic microswimmer in a purely viscous fluid exhibits "viscoelastic" effects as a whole [23,24].…”

Section: Introductionmentioning

confidence: 91%

Reciprocal microswimmers in a viscoelastic fluid

Yasuda,

Kuroda,

Komura

2020

Preprint

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We suggest several reciprocal swimming mechanisms that lead to a locomotion only in viscoelastic fluids. The first situation is to have a difference between the two amplitudes of the oscillatory arm motion for a three-sphere microswimmer. The second situation is when one of the frequencies of the arm motion is twice as large as the other one for a three-sphere microswimmer. The third situation is when the sphere sizes are different for a two-sphere microswimmer. In all these three cases, the average velocity is proportional to the imaginary part of the complex shear viscosity of a surrounding viscoelastic medium. It is essential for a micromachine to break its structural symmetry in order to swim in a viscoelastic fluid by performing reciprocal body motions.

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Section: Introductionmentioning

confidence: 91%

Reciprocal microswimmers in a viscoelastic fluid

Yasuda,

Kuroda,

Komura

2020

Preprint

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“…[67] and analytically in Refs. [68] and [69]. A generalization of the BG model for a system of two coupled noisy Kuramoto oscillators, i.e., oscillators coupled by a periodic cosine potential instead of a harmonic spring, has been discussed in Ref.…”

Section: The Modelmentioning

confidence: 99%

Spectral fingerprints of non-equilibrium dynamics: The case of a Brownian gyrator

Cerasoli,

Ciliberto,

Marinari

et al. 2022

Preprint

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The same system can exhibit a completely different dynamical behavior when it evolves in equilibrium conditions or when it is driven out-of-equilibrium by, e.g., connecting some of its components to heat baths kept at different temperatures. Here we concentrate on an analytically solvable and experimentally-relevant model of such a system -the so-called Brownian gyrator -a twodimensional nanomachine that performs a systematic, on average, rotation around the origin under non-equilibrium conditions, while no net rotation takes place in equilibrium. On this example, we discuss a question whether it is possible to distinguish between two types of a behavior judging not upon the statistical properties of the trajectories of components, but rather upon their respective spectral densities. The latter are widely used to characterize diverse dynamical systems and are routinely calculated from the data using standard built-in packages. From such a perspective, we inquire whether the power spectral densities possess some "fingerprint" properties specific to the behavior in non-equilibrium. We show that indeed one can conclusively distinguish between equilibrium and non-equilibrium dynamics by analyzing the cross-correlations between the spectral densities of both components in the short frequency limit, or from the spectral densities of both components evaluated at zero frequency. Our analytical predictions, corroborated by experimental and numerical results, open a new direction for the analysis of a non-equilibrium dynamics.

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“…The resulting probability flux can be expressed in terms of a frequency matrix to characterize a non-equilibrium steady-state [22,23]. Importantly, we have obtained a linear relation between the eigenvalue of the frequency matrix and the average velocity of a thermally driven micromachine [21].…”

Section: Introductionmentioning

confidence: 99%

“…For non-equilibrium steady-state situations, however, detailed balance is broken and a probability flux loop exists in a configuration phase space [17][18][19][20]. Recently, the present authors discussed the non-equilibrium * komura@tmu.ac.jp steady-state probability distribution function of a thermally driven three-sphere micromachine and calculated its probability flux in the corresponding configuration space [21]. The resulting probability flux can be expressed in terms of a frequency matrix to characterize a non-equilibrium steady-state [22,23].…”

Section: Introductionmentioning

confidence: 99%

Irreversibility and entropy production of a thermally driven micromachine

Sou,

Hosaka,

Yasuda

et al. 2020

Preprint

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We discuss the non-equilibrium properties of a thermally driven micromachine consisting of three spheres which are in equilibrium with independent heat baths characterized by different temperatures. Within the framework of a linear stochastic Langevin description, we calculate the timedependent average irreversibility that takes a maximum value for a finite time. This time scale is roughly set by the spring relaxation time. The steady-state average entropy production rate is obtained in terms of the temperatures and the friction coefficients of the spheres. The average entropy production rate depends on thermal and/or mechanical asymmetry of a three-sphere micromachine. We also obtain the center of mass diffusion coefficient of a thermally driven three-sphere micromachine as a function of different temperatures and friction coefficients. With the results of the total entropy production rate and the diffusion coefficient, we finally discuss the efficiency of a thermally driven micromachine.

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Nonequilibrium probability flux of a thermally driven micromachine

Cited by 27 publications

References 41 publications

Reciprocal microswimmers in a viscoelastic fluid

Reciprocal microswimmers in a viscoelastic fluid

Spectral fingerprints of non-equilibrium dynamics: The case of a Brownian gyrator

Irreversibility and entropy production of a thermally driven micromachine

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