标题： 晚期的快速中微子味转换 显示英文标题

标题： Fast Neutrino Flavor Conversion at Late Time

摘要： 我们都知道，在恒星致密各向异性的内部，中微子-中微子前向散射可能导致快速集体中微子振荡，这对与味相关的中微子发射有显著影响，并且对超新星的演化及其中微子信号至关重要。这种密集中微子系统的味演化由大量耦合的非线性偏微分方程支配，这些方程几乎总是非常难以求解。尽管通过“线性稳定性分析”已经理解了触发、初始线性增长以及快速振荡发生的条件，但这一方法无法回答一个重要问题：“快速味转换对可观察的中微子通量或超新星爆炸机制有何影响？”这是一个更为困难的问题，需要理解非线性区域中最终状态解的性质。为了向这个方向迈进，我们提出了在非稳态和非均匀的密集中微子系统中，考虑一维空间和速度模式谱的情况下，关于耦合味演化的第一个数值和解析研究。这项工作清晰地描绘了此类系统的最终状态味动力学，指明了其对时空坐标、相空间变量以及轻子不对称性的依赖关系，因此即使对于最现实的场景，也对超新星天体物理学及其相关的中微子现象学具有重要意义。 显示英文摘要

摘要： We all know that in the dense anisotropic interior of the star, neutrino-neutrino forward-scattering can lead to fast collective neutrino oscillations, which has striking consequences on flavor dependent neutrino emission and can be crucial for the evolution of a supernova and its neutrino signal. The flavor evolution of such dense neutrino system is governed by a large number of coupled nonlinear partial differential equations which are almost always very difficult to solve. Although the triggering, initial linear growth and the condition for fast oscillations to occur are understood by "Linear stability analysis" but this fails to answer an important question: "what is the impact of fast flavor conversion on observable neutrino fluxes or the supernova explosion mechanism?". This is a significantly harder problem that requires understanding the nature of the final state solution in the nonlinear regime. Moving towards this direction we present one of the first numerical as well as an analytical study of the coupled flavor evolution of a non-stationary and inhomogeneous dense neutrino system in the nonlinear regime considering one spatial dimension and a spectrum of velocity modes. This work gives a clear picture of the final state flavor dynamics of such systems specifying its dependence on space-time coordinates, phase space variables as well as the lepton asymmetry and thus can have significant implications for the supernova astrophysics as well as its associated neutrino phenomenology even for the most realistic scenario.