BGK subgrid model for neutrino quantum kinetics

Fuente: arXiv
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Auteurs principaux: Nagakura, Hiroki, Johns, Lucas, Zaizen, Masamichi
Format: Preprint
Publié: 2023
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author Nagakura, Hiroki
Johns, Lucas
Zaizen, Masamichi
author_facet Nagakura, Hiroki
Johns, Lucas
Zaizen, Masamichi
contents We present a new subgrid model for neutrino quantum kinetics, which is primarily designed to incorporate effects of collective neutrino oscillations into neutrino-radiation-hydrodynamic simulations for core-collapse supernovae and mergers of compact objects. We approximate the neutrino oscillation term in quantum kinetic equation by Bhatnagar-Gross-Krook (BGK) relaxation-time prescription, and the transport equation is directly applicable for classical neutrino transport schemes. The BGK model is motivated by recent theoretical indications that non-linear phases of collective neutrino oscillations settle into quasi-steady structures. We explicitly provide basic equations of the BGK subgrid model for both multi-angle and moment-based neutrino transport to facilitate the implementation of the subgrid model in the existing neutrino transport schemes. We also show the capability of our BGK subgrid model by comparing to fully quantum kinetic simulations for fast neutrino-flavor conversion. We find that the overall properties can be well reproduced in the subgrid model; the error of angular-averaged survival probability of neutrinos is within $\sim 20 \%$. By identifying the source of error, we also discuss perspectives to improve the accuracy of the subgrid model.
format Preprint
id arxiv_https___arxiv_org_abs_2312_16285
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle BGK subgrid model for neutrino quantum kinetics
Nagakura, Hiroki
Johns, Lucas
Zaizen, Masamichi
High Energy Astrophysical Phenomena
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
Computational Physics
We present a new subgrid model for neutrino quantum kinetics, which is primarily designed to incorporate effects of collective neutrino oscillations into neutrino-radiation-hydrodynamic simulations for core-collapse supernovae and mergers of compact objects. We approximate the neutrino oscillation term in quantum kinetic equation by Bhatnagar-Gross-Krook (BGK) relaxation-time prescription, and the transport equation is directly applicable for classical neutrino transport schemes. The BGK model is motivated by recent theoretical indications that non-linear phases of collective neutrino oscillations settle into quasi-steady structures. We explicitly provide basic equations of the BGK subgrid model for both multi-angle and moment-based neutrino transport to facilitate the implementation of the subgrid model in the existing neutrino transport schemes. We also show the capability of our BGK subgrid model by comparing to fully quantum kinetic simulations for fast neutrino-flavor conversion. We find that the overall properties can be well reproduced in the subgrid model; the error of angular-averaged survival probability of neutrinos is within $\sim 20 \%$. By identifying the source of error, we also discuss perspectives to improve the accuracy of the subgrid model.
title BGK subgrid model for neutrino quantum kinetics
topic High Energy Astrophysical Phenomena
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
Computational Physics
url https://arxiv.org/abs/2312.16285