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A field-theory approach for modeling dissipative relativistic fluids

A field-theory approach for modeling dissipative relativistic fluids
A field-theory approach for modeling dissipative relativistic fluids

We develop an action principle for producing a single-fluid two-constituent system with dissipation in general relativity. The two constituents in the model are particles and entropy. The particle flux creation rate is taken to be zero, while the entropy creation rate is non-zero. Building on previous work, it is demonstrated that a new term (the proper time derivative of the matter space “metric”) is required in the Lagrangian in order to produce terms typically associated with bulk and shear viscosity. Equations of motion, entropy creation rate, and energy–momentum–stress tensor are derived. Using an Onsager approach of identifying thermodynamic “forces” and “fluxes”, a model is produced which delivers the same entropy creation rate as the standard, relativistic Navier–Stokes equations. This result is then contrasted with a model generated in the spirit of the action principle, which takes as its starting point a specific Lagrangian and then produces the equations of motion, entropy creation rate, and energy–momentum–stress tensor. Unlike the equations derived from Onsager reasoning, where the analogs of the bulk and shear viscosity coefficients are prescribed “externally”, we find that the forms of the coefficients in the second example are a direct result of the specified Lagrangian. Furthermore, the coefficients are shown to satisfy evolution equations along the fluid worldline, also a product of the specific Lagrangian.

dissipation, field theory, relativistic fluids
1099-4300
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Celora, Thomas
b15e9792-aae0-479a-83c5-b5c874b19fa6
Comer, Gregory
844e5be1-aab1-4406-a5c7-951e4988268f
Hawke, Ian
fc964672-c794-4260-a972-eaf818e7c9f4
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Celora, Thomas
b15e9792-aae0-479a-83c5-b5c874b19fa6
Comer, Gregory
844e5be1-aab1-4406-a5c7-951e4988268f
Hawke, Ian
fc964672-c794-4260-a972-eaf818e7c9f4

Andersson, Nils, Celora, Thomas, Comer, Gregory and Hawke, Ian (2024) A field-theory approach for modeling dissipative relativistic fluids. Entropy, 26 (8), [621]. (doi:10.3390/e26080621).

Record type: Article

Abstract

We develop an action principle for producing a single-fluid two-constituent system with dissipation in general relativity. The two constituents in the model are particles and entropy. The particle flux creation rate is taken to be zero, while the entropy creation rate is non-zero. Building on previous work, it is demonstrated that a new term (the proper time derivative of the matter space “metric”) is required in the Lagrangian in order to produce terms typically associated with bulk and shear viscosity. Equations of motion, entropy creation rate, and energy–momentum–stress tensor are derived. Using an Onsager approach of identifying thermodynamic “forces” and “fluxes”, a model is produced which delivers the same entropy creation rate as the standard, relativistic Navier–Stokes equations. This result is then contrasted with a model generated in the spirit of the action principle, which takes as its starting point a specific Lagrangian and then produces the equations of motion, entropy creation rate, and energy–momentum–stress tensor. Unlike the equations derived from Onsager reasoning, where the analogs of the bulk and shear viscosity coefficients are prescribed “externally”, we find that the forms of the coefficients in the second example are a direct result of the specified Lagrangian. Furthermore, the coefficients are shown to satisfy evolution equations along the fluid worldline, also a product of the specific Lagrangian.

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Accepted/In Press date: 22 July 2024
Published date: 24 July 2024
Keywords: dissipation, field theory, relativistic fluids

Identifiers

Local EPrints ID: 495878
URI: http://eprints.soton.ac.uk/id/eprint/495878
ISSN: 1099-4300
PURE UUID: b93d9ff1-8bdd-4c37-bc12-df6c7c63e305
ORCID for Nils Andersson: ORCID iD orcid.org/0000-0001-8550-3843
ORCID for Thomas Celora: ORCID iD orcid.org/0000-0002-6515-3644
ORCID for Ian Hawke: ORCID iD orcid.org/0000-0003-4805-0309

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Date deposited: 26 Nov 2024 17:45
Last modified: 27 Nov 2024 02:39

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Contributors

Author: Nils Andersson ORCID iD
Author: Thomas Celora ORCID iD
Author: Gregory Comer
Author: Ian Hawke ORCID iD

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