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arXiv · 2410.00719

Quantum Closures for Neutrino Moment Transport

James P. Kneller·Julien Froustey·Evan B. Grohs·Francois Foucart·Gail C. McLaughlin·Sherwood Richers
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Abstract

A computationally efficient method for calculating the transport of neutrino flavor in simulations is to use angular moments of the neutrino one-body reduced density matrix, i.e., `quantum moments'. As with any moment-based radiation transport method, a closure is needed if the infinite tower of moment evolution equations is truncated. We derive a general parameterization of a quantum closure and the limits the parameters must satisfy in order for the closure to be physical. We then derive from multi-angle calculations the evolution of the closure parameters in two test cases which we then progressively insert into a moment evolution code and show how the parameters affect the moment results until the full multi-angle results are reproduced. This parameterization paves the way to setting prescriptions for genuine quantum closures adapted to neutrino transport in a range of situations.

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James P. Kneller, Julien Froustey, Evan B. Grohs, Francois Foucart, Gail C. McLaughlin, Sherwood Richers. 2024-10-01. Quantum Closures for Neutrino Moment Transport. https://doi.org/10.1103/physrevd.111.063046

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