Coherence and mixedness of neutrino oscillations in a magnetic field

TL;DR

This paper investigates how neutrino oscillations in a stochastic magnetic field can generate and sustain quantum coherence during dissipative evolution, revealing persistent coherence oscillations and thermalization effects.

Contribution

It provides exact analytical results for quantum coherence in neutrino oscillations under dissipative conditions, highlighting coherence generation from zero initial states.

Findings

Quantum coherence oscillates persistently during dissipative evolution.

Initial spin-polarized states thermalize with equal probabilities for spin states.

Neutrino flavor states also thermalize, but flavor populations remain unequal.

Abstract

The radical departure from classical physics implies quantum coherence, i.e., coherent superposition of eigenstates of Hermitian operators with a discrete spectrum. In resource theory, quantum coherence is a resource for quantum operations. Typically the stochastic phenomenon induces decoherence effects. However, in the present work, we prove that nonunitary evolution leads to the generation of quantum coherence in some cases. Specifically, we consider the neutrino propagation in the dissipative environment, namely in a magnetic field with a stochastic component, and focus on neutrino flavor, spin and spin-flavor oscillations. We present exact analytical results for quantum coherence in neutrino oscillations quantified in terms of the relative entropy. Starting from an initial zero coherence state, we observe persistent oscillations of coherence during the dissipative evolution. We found that after dissipative evolution, the initial spin-polarized state entirely thermalizes, and in the final steady state, the spin-up/down states have the same probabilities. On the other hand, neutrino flavor states also thermalize, byt the populations of two flavor states do not equate to each other. The initial flavor still dominates in the final steady state