探討一維高密度微中子氣體中的快速味轉換：關於三味系統的分析

Abstract

這篇論文探討了一維高密度微中子氣體中的快速味轉換（FFC），並著重於三味系統的分析。FFC在例如核塌縮超新星（CCSNe）和中子星合併（NSMs）等極端的天文環境中是十分重要的。然而過去關於FFC的研究僅著重於考慮e和x的兩味近似系統，本研究將會考慮包含e、μ、以及τ在內的完整三味系統。

我們使用數值模擬方法來演化系統，並且通過改變不同的初始條件來探討三味系統的各式特徵。我們對三味系統進行了不穩定性分析（Instability analysis），並觀察到在兩味系統中未曾觀察過的新特徵，同時探討了緲子－陶子不對稱性對於系統的影響。

我們的研究探討了極端天文環境裡微中子的性質，同時強調了研究三味系統的必要性。這份研究能讓我們深入理解極端環境下微中子的基本性質，並為未來三味系統FFC的研究奠定基礎。

This thesis examines the fast flavor conversion (FFC) in one-dimensional dense neutrino gases, focusing on a comprehensive three-flavor scenario. Fast flavor conversions are essential in elucidating neutrino behavior in extreme astrophysical environments, such as core-collapse supernovae (CCSNe) and neutron star mergers (NSMs). Unlike traditional studies that rely on a two-flavor approximation, this research considers the full three-flavor system involving electron, muon, and tau neutrinos.

We use numerical simulation to evolve the system, studying the different phenomena of the three-flavor system by possessing different initial conditions. An instability analysis for three flavor systems is performed, revealing new features that are not present in two-flavor approximations. We also explore the impact of μτ asymmetry on the system, demonstrating how increasing asymmetry influences flavor evolution.

Our results provide deeper insights into the collective behavior of neutrinos in dense astrophysical environments, highlighting the necessity of considering all three flavors to capture the full complexity of fast flavor conversions. This work contributes to the fundamental understanding of neutrino dynamics and sets the stage for future studies in three-flavor neutrino systems.