Entanglement and Many-Body effects in Collective Neutrino Oscillations

TL;DR

This paper investigates the many-body quantum effects in collective neutrino oscillations, demonstrating how entanglement influences the dynamics and suggesting efficient simulation methods beyond mean-field approximations.

Contribution

It introduces a spin model analyzed with Matrix Product States to explore many-body correlations and entanglement in neutrino oscillations, advancing beyond mean-field approaches.

Findings

Entanglement entropies scale logarithmically with system size.

Many-body correlations can trigger bipolar oscillations.

Tensor network methods may efficiently simulate neutrino dynamics.

Abstract

Collective neutrino oscillations play a crucial role in transporting lepton flavor in astrophysical settings, such as supernovae, where the neutrino density is large. In this regime, neutrino-neutrino interactions are important and simulations in the mean-field approximation show evidence for collective oscillations occurring at time scales much larger than those associated with vacuum oscillations. In this work, we study the out-of-equilibrium dynamics of a corresponding spin model using Matrix Product States and show how collective bipolar oscillations can be triggered by many-body correlations if appropriate initial conditions are present. We find entanglement entropies scaling at most logarithmically in the system size suggesting that classical tensor network methods could be efficient in describing collective neutrino dynamics more generally. These observation provide a clear path forward, not only to increase the accuracy of current simulations, but also to elucidate the mechanism behind collective flavor oscillations without resorting to the mean field approximation.