Neutrino many-body flavor evolution: The full Hamiltonian

Journal Article · 19 December 2024 · Physical Review. D.

DOI: https://doi.org/10.1103/PhysRevD.110.123028 · OSTI ID:2483371

Cirigliano, Vincenzo ; Sen, Srimoyee ; Yamauchi, Yukari

We study neutrino flavor evolution in the quantum many-body approach using the full neutrino-neutrino Hamiltonian, including the usually neglected terms that mediate nonforward scattering processes. Working in the occupation number representation with plane waves as single-particle states, we explore the time evolution of simple initial states with up to $N=10$ neutrinos. We discuss the time evolution of the Loschmidt echo, one body flavor and kinetic observables, and the one-body entanglement entropy. For the small systems considered, we observe “thermalization” of both flavor and momentum degrees of freedom on comparable time scales, with results converging towards expectation values computed within a microcanonical ensemble. We also observe that the inclusion of nonforward processes generates a faster flavor evolution compared to the one induced by the truncated (forward) Hamiltonian. Published by the American Physical Society 2024

• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: FG02-00ER41132; SC0021892
• OSTI ID: 2483371
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 12 Vol. 110; ISSN PRVDAQ; ISSN 2470-0010
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English