Gapless non-hydrodynamic modes in relativistic kinetic theory

Fuente: arXiv
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Auteur principal: Gavassino, Lorenzo
Format: Preprint
Publié: 2024
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author Gavassino, Lorenzo
author_facet Gavassino, Lorenzo
contents We provide rigorous criteria to determine whether the non-hydrodynamic sector of a relativistic kinetic theory is gapless. These general criteria apply to both Boltzmann's equation and approximate models thereof, provided that the latter are consistent with thermodynamic principles. As an application of these criteria, we prove that the non-hydrodynamic sector is gapless whenever the scattering cross-section decays to zero at large energies. Physically, this happens because, if particles with very high energy (compared to the temperature) are free streaming, we can use them to build hot non-hydrodynamic waves, which live longer than any hydrodynamic wave. Since many standard cross-sections in quantum field theory vanish at high energies, the existence of these non-thermal long-lived waves is a rather general feature of relativistic systems.
format Preprint
id arxiv_https___arxiv_org_abs_2404_12327
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Gapless non-hydrodynamic modes in relativistic kinetic theory
Gavassino, Lorenzo
Nuclear Theory
High Energy Physics - Theory
Mathematical Physics
We provide rigorous criteria to determine whether the non-hydrodynamic sector of a relativistic kinetic theory is gapless. These general criteria apply to both Boltzmann's equation and approximate models thereof, provided that the latter are consistent with thermodynamic principles. As an application of these criteria, we prove that the non-hydrodynamic sector is gapless whenever the scattering cross-section decays to zero at large energies. Physically, this happens because, if particles with very high energy (compared to the temperature) are free streaming, we can use them to build hot non-hydrodynamic waves, which live longer than any hydrodynamic wave. Since many standard cross-sections in quantum field theory vanish at high energies, the existence of these non-thermal long-lived waves is a rather general feature of relativistic systems.
title Gapless non-hydrodynamic modes in relativistic kinetic theory
topic Nuclear Theory
High Energy Physics - Theory
Mathematical Physics
url https://arxiv.org/abs/2404.12327