Ideal bulk pressure of active Brownian particles

Autoren

Thomas Speck
Robert L Jack

DOI

10.1103/physreve.93.062605

eISSN

2470-0053

ISSN

2470-0045

Ausgabe der Veröffentlichung

6

Zeitschrift

Physical Review E

Sprache

en

Artikelnummer

062605

Online publication date

2016

Status

Published online

Herausgeber

American Physical Society (APS)

Herausgeber URL

http://dx.doi.org/10.1103/physreve.93.062605

Datum der Datenerfassung

2017

Titel

Ideal bulk pressure of active Brownian particles

Ausgabe der Zeitschrift

93

Data source: Crossref

Abstract

The extent to which active matter might be described by effective equilibrium concepts like temperature and pressure is currently being discussed intensely. Here, we study the simplest model, an ideal gas of noninteracting active Brownian particles. While the mechanical pressure exerted onto confining walls has been linked to correlations between particles' positions and their orientations, we show that these correlations are entirely controlled by boundary effects. We also consider a definition of local pressure, which describes interparticle forces in terms of momentum exchange between different regions of the system. We present three pieces of analytical evidence which indicate that such a local pressure exists, and we show that its bulk value differs from the mechanical pressure exerted on the walls of the system. We attribute this difference to the fact that the local pressure in the bulk does not depend on boundary effects, contrary to the mechanical pressure. We carefully examine these boundary effects using a channel geometry, and we show a virial formula for the pressure correctly predicts the mechanical pressure even in finite channels. However, this result no longer holds in more complex geometries, as exemplified for a channel that includes circular obstacles.

Addresses

Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7-9, 55128 Mainz, Germany.

Autoren

Thomas Speck
Robert L Jack

DOI

10.1103/physreve.93.062605

eISSN

2470-0053

Externe Identifier

PubMed Identifier: 27415318

Funding acknowledgements

Deutsche Forschungsgemeinschaft: SP 1382/3-1

Open access

false

ISSN

2470-0045

Ausgabe der Veröffentlichung

6

Zeitschrift

Physical review. E

Sprache

eng

Medium

Print-Electronic

Online publication date

2016

Paginierung

062605

Datum der Veröffentlichung

2016

Status

Published

Datum der Datenerfassung

2016

Titel

Ideal bulk pressure of active Brownian particles.

Sub types

Journal Article

Ausgabe der Zeitschrift

93

Data source: Europe PubMed Central

Abstract

The extent to which active matter might be described by effective equilibrium concepts like temperature and pressure is currently being discussed intensely. Here, we study the simplest model, an ideal gas of noninteracting active Brownian particles. While the mechanical pressure exerted onto confining walls has been linked to correlations between particles' positions and their orientations, we show that these correlations are entirely controlled by boundary effects. We also consider a definition of local pressure, which describes interparticle forces in terms of momentum exchange between different regions of the system. We present three pieces of analytical evidence which indicate that such a local pressure exists, and we show that its bulk value differs from the mechanical pressure exerted on the walls of the system. We attribute this difference to the fact that the local pressure in the bulk does not depend on boundary effects, contrary to the mechanical pressure. We carefully examine these boundary effects using a channel geometry, and we show a virial formula for the pressure correctly predicts the mechanical pressure even in finite channels. However, this result no longer holds in more complex geometries, as exemplified for a channel that includes circular obstacles.

Autoren

Thomas Speck
Robert L Jack

Autoren-URL

https://www.ncbi.nlm.nih.gov/pubmed/27415318

DOI

10.1103/PhysRevE.93.062605

eISSN

2470-0053

Ausgabe der Veröffentlichung

6

Zeitschrift

Phys Rev E

Sprache

eng

Country

United States

Paginierung

062605

Datum der Veröffentlichung

2016

Status

Published

Datum, an dem der Datensatz öffentlich gemacht wurde

2018

Titel

Ideal bulk pressure of active Brownian particles.

Sub types

Journal Article

Ausgabe der Zeitschrift

93

Data source: PubMed

Abstract

The extent to which active matter might be described by effective equilibrium concepts like temperature and pressure is currently being discussed intensely. Here we study the simplest model, an ideal gas of non-interacting active Brownian particles. While the mechanical pressure exerted onto confining walls has been linked to correlations between particles' positions and their orientations, we show that these correlations are entirely controlled by boundary effects. We also consider a definition of local pressure, which describes interparticle forces in terms of momentum exchange between different regions of the system. We present three pieces of analytical evidence which indicate that such a local pressure exists, and we show that its bulk value differs from the mechanical pressure exerted on the walls of the system. We attribute this difference to the fact that the local pressure in the bulk does not depend on boundary effects, contrary to the mechanical pressure. We carefully examine these boundary effects using a channel geometry, and we show a virial formula for the pressure correctly predicts the mechanical pressure even in finite channels. However, this result no longer holds in more complex geometries, as exemplified for a channel that includes circular obstacles.

Autoren

Thomas Speck
Robert L Jack

Autoren-URL

http://arxiv.org/abs/1512.00830v2

Zeitschrift

Phys. Rev. E

Schlüsselwörter

cond-mat.stat-mech
cond-mat.stat-mech
cond-mat.soft

Paginierung

062605

Datum der Veröffentlichung

2015

Herausgeber URL

http://dx.doi.org/10.1103/PhysRevE.93.062605

Datum der Datenerfassung

2015

Datum, an dem der Datensatz öffentlich gemacht wurde

2015

Titel

Ideal bulk pressure of active Brownian particles

Ausgabe der Zeitschrift

93

Files

1512.00830v2.pdf

Data source: arXiv

Ideal bulk pressure of active Brownian particles

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