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Main Authors: Jose, Stephy, Rosso, Alberto, Ramola, Kabir
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2306.13613
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author Jose, Stephy
Rosso, Alberto
Ramola, Kabir
author_facet Jose, Stephy
Rosso, Alberto
Ramola, Kabir
contents We present exact results for the fluctuations in the number of particles crossing the origin up to time $t$ in a collection of non-interacting run and tumble particles in one dimension. In contrast to passive systems, such active particles are endowed with two inherent degrees of freedom: positions and velocities, which can be used to construct density and magnetization fields. We introduce generalized disorder averages associated with both these fields and perform annealed and quenched averages over various initial conditions. We show that the variance $σ^2$ of the current in annealed versus quenched magnetization situations exhibits a surprising difference at short times: $σ^2 \sim t$ versus $σ^2 \sim t^2$ respectively, with a $\sqrt{t}$ behavior emerging at large times. Our analytical results demonstrate that in the strictly quenched scenario, where both the density and magnetization fields are initially frozen, the fluctuations in the current are strongly suppressed. Importantly, these anomalous fluctuations cannot be obtained solely by freezing the density field.
format Preprint
id arxiv_https___arxiv_org_abs_2306_13613
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Generalized disorder averages and current fluctuations in run and tumble particles
Jose, Stephy
Rosso, Alberto
Ramola, Kabir
Statistical Mechanics
We present exact results for the fluctuations in the number of particles crossing the origin up to time $t$ in a collection of non-interacting run and tumble particles in one dimension. In contrast to passive systems, such active particles are endowed with two inherent degrees of freedom: positions and velocities, which can be used to construct density and magnetization fields. We introduce generalized disorder averages associated with both these fields and perform annealed and quenched averages over various initial conditions. We show that the variance $σ^2$ of the current in annealed versus quenched magnetization situations exhibits a surprising difference at short times: $σ^2 \sim t$ versus $σ^2 \sim t^2$ respectively, with a $\sqrt{t}$ behavior emerging at large times. Our analytical results demonstrate that in the strictly quenched scenario, where both the density and magnetization fields are initially frozen, the fluctuations in the current are strongly suppressed. Importantly, these anomalous fluctuations cannot be obtained solely by freezing the density field.
title Generalized disorder averages and current fluctuations in run and tumble particles
topic Statistical Mechanics
url https://arxiv.org/abs/2306.13613