PhD Defense: Marie Cornelius Hansen

Title: Fast neutrino flavor conversion in core-collapse supernovae

Abstract: In dense astrophysical media, such as the innermost regions of core-collapse supernovae, neutrinos experience coherent forward scattering off each other which can lead to collective flavor conversion. This non-linear flavor evolution can influence the supernova explosion dynamics and the composition of the ejected material. Modeling neutrino flavor conversion in dense environments remains a major theoretical and computational challenge. A consistent quantum-kinetic treatment must couple flavor conversion, collisions with the background medium, and transport within multi-dimensional hydrodynamics—linking phenomena that occur on vastly different scales. This thesis addresses these challenges through two complementary approaches. First, it explores neutrino flavor conversion in one and two spatial dimensions in the supernova core. Second, it identifies where and when the conditions for flavor conversion—specifically, crossings in the electron-neutrino lepton number distribution—arise in core-collapse supernova simulations. The overarching goal of this thesis is to clarify under which circumstances flavor conversion is likely to occur, bridging the microscopic physics of neutrino flavor evolution with the macroscopic physics of core-collapse supernovae.

Time: Tuesday, December 9, 9.30am

Place: Auditorium A, Blegdamsvej 17

The thesis is available for consultation in Irene’s office.