# Neutrino quantum kinetics in a core-collapse supernova

Source: [Neutrino quantum kinetics in a core-collapse supernova](<https://www.sota2.com/research/paper/68fa48111e209131ce92ce93>)

Collection index: [llms.txt](<https://www.sota2.com/research/llms.txt>)

Data updated: 2025-10-27T04:32:07.060Z

Authors: Shashank Shalgar, Irene Tamborra

Published: 2024-06-13T18:00:02.000Z

## Abstract

Our understanding of neutrino flavor conversion in the supernova core is still preliminary, despite its likely relevance to the neutrino-driven supernova mechanism. We present multi-angle and multi-energy numerical simulations of neutrino quantum kinetics within a spherically symmetric shell in the proximity of the region of neutrino decoupling. We rely on inputs from a one-dimensional core-collapse supernova model with a mass of $18.6\\ M\_\\odot$ and find that, at early post-bounce times ($t\_{\\mathrm pb} \\lesssim 0.5$~s), no crossing is present in the angular distribution of the electron neutrino lepton number and flavor conversion is triggered by slow collective instabilities. Angular crossings appear for $t\_{\\textrm{pb}} \\gtrsim 0.5$~s and fast flavor conversion leads to flavor equipartition, with the spectral energy distribution of $\\nu\_{e}$ ($\\bar{\\nu}\_{e}$) and $\\nu\_{x}$ ($\\bar{\\nu}\_{x}$) becoming comparable. Notably, flavor equipartition is not a generic outcome of fast flavor conversion, rather it is a consequence of the relatively similar properties of neutrinos of different flavors characterizing the late accretion phase. Artificially tweaking the collision term to introduce an electron lepton number angular crossing for $t\_{\\mathrm{pb}} \\lesssim 0.05$~s, we observe that flavor equipartition is not achieved. While our findings are restricted to a specific supernova model, and they only take into account the feedback of the neutrino background on the flavor conversion, they suggest a rich phenomenology in the supernova core as a function of the post-bounce time which needs to be further explored to assess its impact on the explosion mechanism.

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## Original sources and implementation

[Original paper](<https://arxiv.org/abs/2406.09504>)

[PDF](<https://arxiv.org/pdf/2406.09504.pdf>)