Infinite Order Hydrodynamics: An Analytical Example

Fuente: arXiv
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Autore principale: Gavassino, Lorenzo
Natura: Preprint
Pubblicazione: 2024
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author Gavassino, Lorenzo
author_facet Gavassino, Lorenzo
contents We construct a kinetic model for matter-radiation interactions whose hydrodynamic gradient expansion can be computed analytically up to infinite order in derivatives, in the fully nonlinear regime, and for arbitrary flows. The frequency dependence of the opacity of matter is chosen to mimic the relaxation time of a self-interacting scalar field. In this way, the transient sector simulates that of a realistic quantum field theory. The gradient series is found to diverge for most flows, in agreement with previous findings. We identify, for the model at hand, the mechanism at the origin of the divergence, and we provide a successful regularization scheme. Additionally, we propose a universal qualitative framework for predicting the breakdown of the gradient expansion of an arbitrary microscopic system undergoing a given flow. This framework correctly recovers all previously known instances of gradient expansion divergence. As a new prediction, we show that the gradient expansion diverges when the energy-dependent mean free path is unbounded above.
format Preprint
id arxiv_https___arxiv_org_abs_2402_19343
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Infinite Order Hydrodynamics: An Analytical Example
Gavassino, Lorenzo
Nuclear Theory
High Energy Astrophysical Phenomena
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
We construct a kinetic model for matter-radiation interactions whose hydrodynamic gradient expansion can be computed analytically up to infinite order in derivatives, in the fully nonlinear regime, and for arbitrary flows. The frequency dependence of the opacity of matter is chosen to mimic the relaxation time of a self-interacting scalar field. In this way, the transient sector simulates that of a realistic quantum field theory. The gradient series is found to diverge for most flows, in agreement with previous findings. We identify, for the model at hand, the mechanism at the origin of the divergence, and we provide a successful regularization scheme. Additionally, we propose a universal qualitative framework for predicting the breakdown of the gradient expansion of an arbitrary microscopic system undergoing a given flow. This framework correctly recovers all previously known instances of gradient expansion divergence. As a new prediction, we show that the gradient expansion diverges when the energy-dependent mean free path is unbounded above.
title Infinite Order Hydrodynamics: An Analytical Example
topic Nuclear Theory
High Energy Astrophysical Phenomena
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
url https://arxiv.org/abs/2402.19343