Motility-induced coexistence of a hot liquid and a cold gas

Fuente: arXiv
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Main Authors: Hecht, Lukas, Dong, Iris, Liebchen, Benno
Format: Preprint
Published: 2023
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author Hecht, Lukas
Dong, Iris
Liebchen, Benno
author_facet Hecht, Lukas
Dong, Iris
Liebchen, Benno
contents If two phases exist at the same time, such as a gas and a liquid, they have the same temperature. This fundamental law of equilibrium physics is known to apply even to many non-equilibrium systems. However, recently, there has been much attention in the finding that inertial self-propelled particles like Janus colloids in a plasma or microflyers could self-organize into a hot gas-like phase that coexists with a colder liquid-like phase. Here, we show that a kinetic temperature difference across coexisting phases can occur even in equilibrium systems when adding generic (overdamped) self-propelled particles. In particular, we consider mixtures of overdamped active and inertial passive Brownian particles and show that when they phase separate into a dense and a dilute phase, both phases have different kinetic temperatures. Surprisingly, we find that the dense phase (liquid) cannot only be colder but also hotter than the dilute phase (gas). This effect hinges on correlated motions where active particles collectively push and heat up passive ones primarily within the dense phase. Our results answer the fundamental question if a non-equilibrium gas can be colder than a coexisting liquid and create a route to equip matter with self-organized domains of different kinetic temperatures.
format Preprint
id arxiv_https___arxiv_org_abs_2311_15638
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Motility-induced coexistence of a hot liquid and a cold gas
Hecht, Lukas
Dong, Iris
Liebchen, Benno
Soft Condensed Matter
Statistical Mechanics
Computational Physics
If two phases exist at the same time, such as a gas and a liquid, they have the same temperature. This fundamental law of equilibrium physics is known to apply even to many non-equilibrium systems. However, recently, there has been much attention in the finding that inertial self-propelled particles like Janus colloids in a plasma or microflyers could self-organize into a hot gas-like phase that coexists with a colder liquid-like phase. Here, we show that a kinetic temperature difference across coexisting phases can occur even in equilibrium systems when adding generic (overdamped) self-propelled particles. In particular, we consider mixtures of overdamped active and inertial passive Brownian particles and show that when they phase separate into a dense and a dilute phase, both phases have different kinetic temperatures. Surprisingly, we find that the dense phase (liquid) cannot only be colder but also hotter than the dilute phase (gas). This effect hinges on correlated motions where active particles collectively push and heat up passive ones primarily within the dense phase. Our results answer the fundamental question if a non-equilibrium gas can be colder than a coexisting liquid and create a route to equip matter with self-organized domains of different kinetic temperatures.
title Motility-induced coexistence of a hot liquid and a cold gas
topic Soft Condensed Matter
Statistical Mechanics
Computational Physics
url https://arxiv.org/abs/2311.15638