TAPIR Seminar

Neutrino transport and their interaction with matter often play a crucial role for high energy astrophysical phenomena such as core collapse supernovae, mergers of compact objects, and accretion disks around black holes. However, the treatment of neutrino transfer coupling with hydrodynamics is quite difficult since it involves a complex combination of microphysics and macrophysics. Therefore an approximate method has been widely used in the community, but the latest results among different groups are still at odds with one another.

Motivated by these facts, we have developed multi-d Boltzmann-Hydro code over the years, and it has been recently implemented in 2D core collapse supernova simulations on the Japanese supercomputer "K". Our Boltzmann solver takes into account all orders of v/c in a novel way, and by virtue of this method, we can handle consistently both collision and advection terms in the Boltzmann equation. Importantly, our code has recently been upgraded to the 3+1 formalism by reformulating the Boltzmann equation in curved spacetime, and now it is ready to be coupled with the Einstein solver. In this seminar, I will introduce our recent progress, and the path towards full GR Boltzmann simulations.