Equilibration Processes of Quantum Many-Neutrino Systems in Core-Collapse
Supernovae
Image Credit: SN 2020fqv in NGC 4568, Credit: NASA, ESA, Ryan Foley (UC Santa Cruz); Image Processing: Joseph DePasquale (STScI)
Student:
Nikoli Ralph
Mentors:
Vincenzo Cirigliano (INSPIRE-HEP, email: cirigv@uw.edu)
Yukari Yamauchi (INSPIRE-HEP, email: yyama122@uw.edu)
Prerequisites:
Basic knowledge of quantum mechanics and statistical mechanics, and basic coding skills, which will be refined during the project.
What Students Will Learn:
The student will learn how neutrinos evolve in a hot and dense astrophysical medium. The first step will involve studying a quantum mechanical treatment of the neutrino dynamics based on the Standard Model. Then the student will learn a few numerical frameworks for simulating neutrino evolution. The student will formulate the neutrino interactions with a varying number of neutrino flavors, and implement numerical simulations. The student will run simulations with various settings, analyze neutrino observables and other properties of the system, and investigate the driving factors of the equilibration of dense neutrino systems.
Expected Project Length:
One year
Project Description:
Neutrinos are perhaps the most mysterious and elusive of the known particles, because they interact very weakly and have tiny masses, the heaviest neutrino being at least a million times lighter than the lightest charged particle. Yet, they play a crucial role in the early universe and the evolution of stars, as in these environments neutrinos are copiously produced and transport most of the energy and entropy. Moreover, observations of solar, atmospheric, reactor, and accelerator neutrinos indicate that a neutrino produced in a given flavor state (electron, muon, or tau) can morph to another flavor state as it evolves, through a quantum mechanical interference effect. In turn, these so-called neutrino oscillations can have a big impact on the neutron-to-proton ratio, a key quantity in determining what elements are synthesized in the early universe and the ejecta surrounding supernovae and neutron star mergers. Employing the neutrino interactions established in Ref. [1], this project will investigate the mechanism of equilibration processes that have been observed in Ref. [1] by extending the study to systems with different numbers of neutrino flavors.
References:
[1] V. Cirigliano, S. Sen, and Y. Yamauchi, Neutrino many-body flavor evolution: the full Hamiltonian (2024), arXiv:2404.16690
[hep-ph].