Quantum coherence between mass eigenstates of a neutrino can be destroyed by its mass-momentum entanglement

TL;DR

This paper demonstrates that mass-momentum entanglement in neutrinos can destroy their quantum coherence, affecting neutrino oscillations and the matter effect, which was previously overlooked.

Contribution

It reveals that neutrino mass-momentum entanglement can cause decoherence, impacting neutrino oscillation analysis and the understanding of matter effects.

Findings

Mass-momentum entanglement destroys neutrino coherence.

Neutrino-electron states become nonseparable after interactions.

Decoherence due to nonseparability affects neutrino propagation in matter.

Abstract

If a neutrino or antineutrino produced in the decay of an unstable particle is not entangled to its accompanying particles, its mass is necessarily correlated with its momentum. In this manuscript, I illustrate that this entanglement would destroy the quantum coherence between the neutrino's mass eigenstates in both the momentum and position representations, which was overlooked by other authors in previous investigations of entanglement and coherence associated with neutrino oscillations. I further point out that the states of a neutrino and an electron become nonseparable after their charged-current interaction. This nonseparability leads to decoherence for neutrinos propagating in matter, but was not taken into consideration in previous investigations of the matter effect.