Fast oscillations, collisionless relaxation, and spurious evolution of supernova neutrino flavor
Fast oscillations, collisionless relaxation, and spurious evolution of supernova neutrino flavor
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DOI：
10.1103/physrevd.102.103017
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发表时间：
2020-09
影响因子：
5
通讯作者：
Lucas Johns;H. Nagakura;G. Fuller;A. Burrows
中科院分区：
文献类型：
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作者：
Lucas Johns;H. Nagakura;G. Fuller;A. Burrows
越来越多的证据表明，至少在一些核心崩塌的超新星中，中微子可能经历了快速风味转换(FFC)。然而，FFC的结果仍然非常不确定。在这里，我们研究了味场功率的级联，从动量空间的大角度尺度到小角度尺度，表明FFC增强了这一过程，从而加速了弛豫。CASCADE还带来了一个计算挑战，即使味场是稳定的：当功率达到计算的最小角度尺度时，截断角矩展开的误差会传播回更大的尺度，对整体进化产生灾难性的影响。本质上，同样的问题促使在等离子体动力学的背景下开展了广泛的工作。这一联系提出了避免虚假进化的新方法，这个问题目前严重限制了现实振荡计算的可行性。
Mounting evidence indicates that neutrinos likely undergo fast flavor conversion (FFC) in at least some core-collapse supernovae. Outcomes of FFC, however, remain highly uncertain. Here we study the cascade of flavor-field power from large angular scales in momentum space down to small ones, showing that FFC enhances this process and thereby hastens relaxation. Cascade also poses a computational challenge, which is present even if the flavor field is stable: When power reaches the smallest angular scale of the calculation, error from truncating the angular-moment expansion propagates back to larger scales, to disastrous effect on the overall evolution. Essentially the same issue has prompted extensive work in the context of plasma kinetics. This link suggests new approaches to averting spurious evolution, a problem that presently puts severe limitations on the feasibility of realistic oscillation calculations.