Destructive effect of fluctuations on the performance of a Brownian gyrator

Fuente: arXiv
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Main Authors: Viot, Pascal, Argun, Aykut, Volpe, Giovanni, Imparato, Alberto, Rondoni, Lamberto, Oshanin, Gleb
Format: Preprint
Published: 2023
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author Viot, Pascal
Argun, Aykut
Volpe, Giovanni
Imparato, Alberto
Rondoni, Lamberto
Oshanin, Gleb
author_facet Viot, Pascal
Argun, Aykut
Volpe, Giovanni
Imparato, Alberto
Rondoni, Lamberto
Oshanin, Gleb
contents The Brownian gyrator (BG) is often called a minimal model of a nano-engine performing a rotational motion, judging solely upon the fact that in non-equilibrium conditions its torque, angular momentum ${\cal L}$ and angular velocity $\cal W$ have non-zero mean values. For a time-discretized model, which is most adapted for the analysis of an essentially discrete-time data garnered in experiments or numerical simulations, we calculate the previously unknown probability density functions (PDFs) of ${\cal L}$ and $\cal W$. For finite time-step $δt$, the PDF of ${\cal L}$ has exponential tails and all moments are therefore well-defined, but the noise-to-signal ratio can attain big values for small $δt$. Conversely, the PDF of ${\cal W}$ exhibits heavy power-law tails and its mean ${\cal W}$ is the only existing moment. The BG is therefore not an engine in the common sense: it does not exhibit regular rotations on each run and its fluctuations are not only a minor nuisance -- on contrary, their effect is completely destructive for the performance. Our theoretical predictions are confirmed by numerical simulations and experimental data. We discuss some plausible improvements
format Preprint
id arxiv_https___arxiv_org_abs_2307_05248
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Destructive effect of fluctuations on the performance of a Brownian gyrator
Viot, Pascal
Argun, Aykut
Volpe, Giovanni
Imparato, Alberto
Rondoni, Lamberto
Oshanin, Gleb
Statistical Mechanics
The Brownian gyrator (BG) is often called a minimal model of a nano-engine performing a rotational motion, judging solely upon the fact that in non-equilibrium conditions its torque, angular momentum ${\cal L}$ and angular velocity $\cal W$ have non-zero mean values. For a time-discretized model, which is most adapted for the analysis of an essentially discrete-time data garnered in experiments or numerical simulations, we calculate the previously unknown probability density functions (PDFs) of ${\cal L}$ and $\cal W$. For finite time-step $δt$, the PDF of ${\cal L}$ has exponential tails and all moments are therefore well-defined, but the noise-to-signal ratio can attain big values for small $δt$. Conversely, the PDF of ${\cal W}$ exhibits heavy power-law tails and its mean ${\cal W}$ is the only existing moment. The BG is therefore not an engine in the common sense: it does not exhibit regular rotations on each run and its fluctuations are not only a minor nuisance -- on contrary, their effect is completely destructive for the performance. Our theoretical predictions are confirmed by numerical simulations and experimental data. We discuss some plausible improvements
title Destructive effect of fluctuations on the performance of a Brownian gyrator
topic Statistical Mechanics
url https://arxiv.org/abs/2307.05248