Once-in-a-lifetime encounter models for neutrino media: From coherent oscillations to flavor equilibration

Abstract

Collective neutrino oscillations are typically studied using the lowest-order quantum kinetic equation, also known as the mean-field approximation. However, some recent quantum many-body simulations suggest that quantum entanglement among neutrinos may be important and may result in flavor equilibration of the neutrino gas. In this work, we develop new quantum models for neutrino gases in which any pair of neutrinos can interact at most once in their lifetimes. A key parameter of our models is $\gamma =\mu \Delta z$, where $\mu$ is the neutrino coupling strength, which is proportional to the neutrino density, and $\Delta z$ is the duration over which a pair of neutrinos can interact each time. Our models reduce to the mean-field approach in the limit $\gamma \to 0$ and achieve flavor equilibration in time $t\gg (\gamma \mu {)}^{-1}$. These models demonstrate the emergence of coherent flavor oscillations from the particle perspective and may help elucidate the role of quantum entanglement in collective neutrino oscillations.

7 pages, 2 figures. Minor changes

References in corpus (5)

• New Developments in Flavor Evolution of a Dense Neutrino Gas
• Self-induced decoherence in dense neutrino gases
• Spectral splits and entanglement entropy in collective neutrino oscillations
• Multi-Neutrino Entanglement and Correlations in Dense Neutrino Systems
• Do we have enough evidence to invalidate the mean-field approximation adopted to model collective neutrino oscillations?

Cited by in corpus (12)

• Neutrino Oscillations in Core-Collapse Supernovae and Neutron Star Mergers
• Qutrit and Qubit Circuits for Three-Flavor Collective Neutrino Oscillations
• Neutrino Flavor Transformation in Neutron Star Mergers
• Thermodynamics of oscillating neutrinos
• Collective Neutrino Oscillations in Three Flavors on Qubit and Qutrit Processors
• Many-Body Simulations of the Fast Flavor Instability
• Exploring entanglement and spectral split correlations in three-flavor collective neutrino oscillations
• Impact of Neutrino Flavor Conversions on Neutron Star Merger Dynamics, Ejecta, Nucleosynthesis, and Multi-Messenger Signals
• Once-in-a-lifetime encounter models for neutrino media II: Quasi-steady states and miscidynamic flavor evolution
• Testing common approximations of neutrino fast flavor conversion
• Two-beam Multiparticle Many-body simulations of Inhomogeneous FFI
• Interactions of Neutrino Wave Packets