Dynamical Phase Transitions in models of Collective Neutrino Oscillations

TL;DR

This paper investigates dynamical phase transitions in models of collective neutrino oscillations, explaining discrepancies in flavor evolution timescales and exploring their implications for astrophysical scenarios.

Contribution

It provides a coherent explanation for the timescale tension in neutrino models through the concept of dynamical phase transitions and examines their impact on realistic oscillation models.

Findings

DPT explains the difference in predicted flavor evolution timescales.

DPT may significantly influence neutrino flavor transport in astrophysical environments.

The study links phase transition phenomena to neutrino oscillation dynamics.

Abstract

Collective neutrino oscillations can potentially play an important role in transporting lepton flavor in astrophysical scenarios where the neutrino density is large, typical examples are the early universe and supernova explosions. It has been argued in the past that simple models of the neutrino Hamiltonian designed to describe forward scattering can support substantial flavor evolution on very short time scales $t\approx\log(N)/(G_F\rho_\nu)$, with $N$ the number of neutrinos, $G_F$ the Fermi constant and $\rho_\nu$ the neutrino density. This finding is in tension with results for similar but exactly solvable models for which $t\approx\sqrt{N}/(G_F\rho_\nu)$ instead. In this work we provide a coherent explanation of this tension in terms of Dynamical Phase Transitions (DPT) and study the possible impact that a DPT could have in more realistic models of neutrino oscillations and their mean-field approximation.