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arXiv · 2605.11062

Neutrino mixing and gravitational production via inflation

Oleg Lebedev·Jong-Hyun Yoon
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Abstract

We develop the Bogolyubov coefficient formalism for gravitational production of fermions with time-dependent mixing, which allows us to study a prototype neutrino system. The neutrino masses and mixings depend on the scalar field values, i.e. the Higgs or singlet scalar expectation values. These are time-dependent in the Early Universe and, due to de Sitter fluctuations, can reach very large values during inflation. As a result, gravitational production of all types of neutrinos can be much enhanced. We obtain an upper bound on the abundance of active and sterile neutrinos produced by classical gravity, $Y \lesssim 10^{-11}$.

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Oleg Lebedev, Jong-Hyun Yoon. 2026-05-11. Neutrino mixing and gravitational production via inflation. https://arxiv.org/abs/2605.11062

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