Field redefinition and its impact in relativistic hydrodynamics

Fuente: arXiv
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Autori principali: Bhattacharyya, Sayantani, Mitra, Sukanya, Roy, Shuvayu, Singh, Rajeev
Natura: Preprint
Pubblicazione: 2024
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author Bhattacharyya, Sayantani
Mitra, Sukanya
Roy, Shuvayu
Singh, Rajeev
author_facet Bhattacharyya, Sayantani
Mitra, Sukanya
Roy, Shuvayu
Singh, Rajeev
contents In this paper, we explore the impact of field redefinition on the spectrum of linearized perturbations in relativistic hydrodynamics. We observe that the spectrum of hydrodynamics modes is never affected by the local field redefinition, however, the spectrum of the non-hydrodynamic modes is affected. Through an appropriate all-order redefinition, non-hydrodynamic modes can be eliminated, leading to a new frame where the spectrum contains only hydrodynamic modes. We also observe that the resulting stress-energy tensor may have an infinite series in momentum space, with a convergence radius linked to the eliminated non-hydrodynamic mode. In certain special cases, higher-order terms in the stress-energy tensor under field redefinition may cancel, indicating that non-hydrodynamic modes are mere artefacts of the fluid variable choice and hold no physical significance, even if they appear to violate physical constraints. Using a special toy example, we find a criterion to distinguish between physical and unphysical non-hydrodynamic modes.
format Preprint
id arxiv_https___arxiv_org_abs_2409_15387
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Field redefinition and its impact in relativistic hydrodynamics
Bhattacharyya, Sayantani
Mitra, Sukanya
Roy, Shuvayu
Singh, Rajeev
Nuclear Theory
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
In this paper, we explore the impact of field redefinition on the spectrum of linearized perturbations in relativistic hydrodynamics. We observe that the spectrum of hydrodynamics modes is never affected by the local field redefinition, however, the spectrum of the non-hydrodynamic modes is affected. Through an appropriate all-order redefinition, non-hydrodynamic modes can be eliminated, leading to a new frame where the spectrum contains only hydrodynamic modes. We also observe that the resulting stress-energy tensor may have an infinite series in momentum space, with a convergence radius linked to the eliminated non-hydrodynamic mode. In certain special cases, higher-order terms in the stress-energy tensor under field redefinition may cancel, indicating that non-hydrodynamic modes are mere artefacts of the fluid variable choice and hold no physical significance, even if they appear to violate physical constraints. Using a special toy example, we find a criterion to distinguish between physical and unphysical non-hydrodynamic modes.
title Field redefinition and its impact in relativistic hydrodynamics
topic Nuclear Theory
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
url https://arxiv.org/abs/2409.15387