In anisotropic neutrino gases, νν-bar pairing instabilities emerge when the excessive pair-occupation number distribution changes sign, producing pair conversions at growth rates comparable to fast flavor instabilities.
Neutrino Quantum Kinetic Equations: The Collision Term
3 Pith papers cite this work. Polarity classification is still indexing.
abstract
We derive the collision term relevant for neutrino quantum kinetic equations in the early universe and compact astrophysical objects, displaying its full matrix structure in both flavor and spin degrees of freedom. We include in our analysis neutrino-neutrino processes, scattering and annihilation with electrons and positrons, and neutrino scattering off nucleons (the latter in the low-density limit). After presenting the general structure of the collision terms, we take two instructive limiting cases. The one-flavor limit highlights the structure in helicity space and allows for a straightforward interpretation of the off-diagonal entries in terms of the product of scattering amplitudes of the two helicity states. The isotropic limit is relevant for studies of the early universe: in this case the terms involving spin coherence vanish and the collision term can be expressed in terms of two-dimensional integrals, suitable for computational implementation.
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In a neutrino-gas model, the many-body Hamiltonian yields different evolution timescales and asymptotics than the quantum kinetic approach with collisions, while quantum resources for the full case sit at the low end for HEP problems and mid-to-high for quantum chemistry.
Many-body neutrino calculations in simple momentum-state configurations yield helicity conversion probabilities orders of magnitude above mean-field results due to momentum exchange.
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Collective neutrino-antineutrino pair oscillations
In anisotropic neutrino gases, νν-bar pairing instabilities emerge when the excessive pair-occupation number distribution changes sign, producing pair conversions at growth rates comparable to fast flavor instabilities.
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Collective neutrino oscillations: Many-body non-forward effects and non-classicality
In a neutrino-gas model, the many-body Hamiltonian yields different evolution timescales and asymptotics than the quantum kinetic approach with collisions, while quantum resources for the full case sit at the low end for HEP problems and mid-to-high for quantum chemistry.
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Neutrino helicity oscillations in astrophysical environments: a many-body approach
Many-body neutrino calculations in simple momentum-state configurations yield helicity conversion probabilities orders of magnitude above mean-field results due to momentum exchange.