Berry phase for oscillating neutrinos

TL;DR

This paper demonstrates the existence of a Berry phase in the time evolution of mixed states, specifically showing that for neutrinos, this phase depends solely on the mixing angle.

Contribution

It reveals the topological Berry phase in mixed neutrino states and establishes its dependence on the mixing angle, a novel insight in neutrino physics.

Findings

Berry phase exists in mixed neutrino states

Berry phase depends only on the mixing angle

Topological nature of the phase is established

Abstract

We show the presence of a topological (Berry) phase in the time evolution of a mixed state. For the case of mixed neutrinos, the Berry phase is a function of the mixing angle only.