Robustness of Solutions of the Quantum Kinetic Equations in the Presence of Matter Density Fluctuations

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Autori principali: Shalgar, Shashank, Gogilashvili, Mariam
Natura: Preprint
Pubblicazione: 2025
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author Shalgar, Shashank
Gogilashvili, Mariam
author_facet Shalgar, Shashank
Gogilashvili, Mariam
contents We investigate the role of fluctuations in the matter density on neutrino flavor evolution by studying their effects on the collision terms in the spherically symmetric quantum kinetics equations (QKEs). We solve the QKEs with varying radial resolution ($r_{\mathrm{bins}} = 150 \, , 1500 \, , 15000$) to assess numerical convergence in angular distributions, number densities, and energy spectra for four neutrino flavors ($ν_e$, $\barν_e$, $ν_x$, $\barν_x$). Our results demonstrate that the solutions are numerically converged already at the coarsest resolution, with higher resolutions yielding almost identical outcomes. We introduce random perturbations to each radial bin, thus adding perturbations with a length scale that is related to the radial resolution. We study both time-independent and time-dependent perturbations to the matter density that affect the collision term and analyze their effects on neutrino flavor evolution. We find that such fluctuations do not induce any significant instabilities or qualitative changes in flavor evolution. Angular structure remains robust, and flavor-dependent number densities and energy spectra show only minor deviations compared to the unperturbed case. These findings suggest that matter perturbations have a negligible effect on neutrino flavor evolution in spherically symmetric settings.
format Preprint
id arxiv_https___arxiv_org_abs_2508_15747
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Robustness of Solutions of the Quantum Kinetic Equations in the Presence of Matter Density Fluctuations
Shalgar, Shashank
Gogilashvili, Mariam
High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
We investigate the role of fluctuations in the matter density on neutrino flavor evolution by studying their effects on the collision terms in the spherically symmetric quantum kinetics equations (QKEs). We solve the QKEs with varying radial resolution ($r_{\mathrm{bins}} = 150 \, , 1500 \, , 15000$) to assess numerical convergence in angular distributions, number densities, and energy spectra for four neutrino flavors ($ν_e$, $\barν_e$, $ν_x$, $\barν_x$). Our results demonstrate that the solutions are numerically converged already at the coarsest resolution, with higher resolutions yielding almost identical outcomes. We introduce random perturbations to each radial bin, thus adding perturbations with a length scale that is related to the radial resolution. We study both time-independent and time-dependent perturbations to the matter density that affect the collision term and analyze their effects on neutrino flavor evolution. We find that such fluctuations do not induce any significant instabilities or qualitative changes in flavor evolution. Angular structure remains robust, and flavor-dependent number densities and energy spectra show only minor deviations compared to the unperturbed case. These findings suggest that matter perturbations have a negligible effect on neutrino flavor evolution in spherically symmetric settings.
title Robustness of Solutions of the Quantum Kinetic Equations in the Presence of Matter Density Fluctuations
topic High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2508.15747