# Neutrino quantum kinetics in two spatial dimensions

**Authors:** Marie Cornelius, Shashank Shalgar, Irene Tamborra  
**arXiv:** [2407.04769](https://arxiv.org/abs/2407.04769)  
**Date:** 2024-07-05  
**Summary page:** https://www.summarizepaper.com/en/paper/2407.04769v1/

## Key points

- Study explores neutrino flavor conversion in core-collapse supernovae and neutron star mergers
- Innovative (2+1+1) dimensional simulation model used to capture flavor evolution dynamics
- Simulation includes non-forward neutral current and charged current collisions, neutrino advection
- Perturbations introduced to mimic real-world fluctuations, leading to qualitative changes in flavor conversion
- Higher levels of flavor conversion alternate across simulation annulus due to perturbations
- Neutrino advection crucial in spreading flavor waves across neighboring spatial regions
- Importance of modeling neutrino quantum kinetics in multiple dimensions highlighted
- Research sheds light on how fluctuations impact flavor evolution and influence compact astrophysical sources

## Summary

In their study, Marie Cornelius, Shashank Shalgar, and Irene Tamborra explore the realm of neutrino flavor conversion within the innermost regions of core-collapse supernovae and neutron star mergers. Traditionally, our understanding has been limited to spherically symmetric configurations that allow for the numerical solution of quantum kinetic equations. However, in this paper, the researchers take a groundbreaking approach by simulating neutrino quantum kinetics in a (2+1+1) dimensional setup. This innovative model incorporates two spatial dimensions, one neutrino momentum variable, and time to capture the intricate dynamics of flavor evolution during neutrino decoupling from matter. The simulation accounts for non-forward neutral current and charged current collisions between neutrinos and the matter background, as well as neutrino advection. To mimic real-world fluctuations in neutrino emission and matter background, perturbations are introduced in both the collision term and the vacuum term of the Hamiltonian. These perturbations disrupt the initial symmetry of the neutrino field across the simulation annulus, leading to qualitative changes in flavor conversion. Regions with higher levels of flavor conversion alternate across the simulation annulus due to these perturbations. Additionally, neutrino advection plays a crucial role in spreading flavor waves across neighboring spatial regions. Despite being based on a simplified setup, this study sheds light on the importance of modeling neutrino quantum kinetics in multiple dimensions. By exploring how fluctuations impact flavor evolution, this research provides valuable insights into how neutrinos influence compact astrophysical sources and nucleosynthesis processes. The findings presented by Cornelius et al. underscore of considering multi-dimensional effects when studying in astrophysical contexts.