Exact solution of multiangle quantum many-body collective neutrino-flavor oscillations
Exact solution of multiangle quantum many-body collective neutrino-flavor oscillations
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DOI：
10.1103/physrevc.101.065805
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发表时间：
2019-05
影响因子：
3.1
通讯作者：
E. Rrapaj
中科院分区：
文献类型：
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作者：
E. Rrapaj
我通过考虑真空贡献、物质效应和中微子自相互作用来研究致密中微子气体的味道演化。假设在均匀物质背景中存在两种风味的系统，计算离散动量空间中多体系统的时间演化。多角度中微子-中微子相互作用得到精确处理，并与单角度近似和平均场计算进行比较。单能双中微子束场景得到了解析求解。我继续解决两个能级的单能立方晶格和二次晶格的风味振荡。此外，我还研究 12、16 和 20 中微子的各种构型。我发现当所有中微子最初具有相同的味道时，所有方法都一致。当两种风味都存在时，我发现集体振荡和风味平衡在多体处理中产生，但在平均场方法中却没有。这种差异在具有微小混合角的致密物质中持续存在，并且可以归因于存在不可忽略的风味偏振相关性。在所有这些情况下，纠缠熵都很重要。超新星或中子星合并的相关性取决于归一化体积 $V$ 的值以及与振荡相关的时间尺度的较大 $N$ 依赖性。在未来的工作中，我打算使用更大的晶格来研究这种依赖性，并且还包括反中微子。
I study the flavor evolution of a dense neutrino gas by considering vacuum contributions, matter effects, and neutrino self-interactions. Assuming a system of two flavors in a uniform matter background, the time evolution of the many-body system in discretized momentum space is computed. The multiangle neutrino-neutrino interactions are treated exactly and compared to both the single-angle approximation and mean-field calculations. The monoenergetic two-neutrino beam scenario is solved analytically. I proceed to solve flavor oscillations for monoenergetic cubic lattices and quadratic lattices of two energy levels. In addition I study various configurations of 12, 16, and 20 neutrinos. I find that when all neutrinos are initially of the same flavor, all methods agree. When both flavors are present, I find collective oscillations and flavor equilibration develop in the many-body treatment but not in the mean-field method. This difference persists in dense matter with tiny mixing angle and it can be ascribed to non-negligible flavor polarization correlations being present. Entanglement entropy is significant in all such cases. The relevance for supernovae or neutron stars mergers is contingent upon the value of the normalization volume $V$ and the large $N$ dependence of the timescale associated with oscillations. In future work, I intend study this dependence using larger lattices and also include antineutrinos.