@article{f66e2582846e4942ab12890abe4f46f1,
title = "Fast oscillations, collisionless relaxation, and spurious evolution of supernova neutrino flavor",
abstract = "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.",
author = "Lucas Johns and Hiroki Nagakura and Fuller, {George M.} and Adam Burrows",
note = "Funding Information: We are grateful to Evan Grohs, Kei Kotake, Zidu Lin, Amol Patwardhan, and Manibrata Sen for stimulating conversations at the INT workshop on “Neutrinos from the Lab to the Cosmos” and to Shashank Shalgar and Irene Tamborra for enjoyable correspondence. Support for this work was provided by NASA through the NASA Hubble Fellowship Grant No. HST-HF2-51461.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. L. J. acknowledges support as a NASA Einstein Fellow. L. J. and G. M. F. acknowledge support from NSF Grant No. PHY-1914242, from the Department of Energy Scientific Discovery through Advanced Computing (SciDAC-4) grant register No. SN60152 (Award No. de-sc0018297), and from the NSF N3AS Hub Grant No. PHY-1630782 and Heising-Simons Foundation Grant No. 2017-22. A. B. acknowledges support from the U.S. Department of Energy Office of Science and the Office of Advanced Scientific Computing Research via the Scientific Discovery through Advanced Computing (SciDAC4) program and Grant DE-SC0018297 (Subaward No. 00009650). In addition, he acknowledges support from the U.S. NSF under Grants No. AST-1714267 and No. PHY-1804048.",
year = "2020",
month = nov,
day = "16",
doi = "10.1103/PhysRevD.102.103017",
language = "English (US)",
volume = "102",
journal = "Physical Review D",
issn = "2470-0010",
publisher = "American Physical Society",
number = "10",
}