Entanglement Entropy Distributions of a Muon Decay

Autor: Shanmuka Shivashankara, Nicole Cafe, Patti Rizzo
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Letters in High Energy Physics, Vol 2024, Iss 1 (2024)
Druh dokumentu: article
ISSN: 2632-2714
DOI: 10.31526/lhep.2024.531
Popis: Divergences that occur in density matrices of decay and scattering processes are shown to be regularized by tracing and unitarity or the optical theorem. These divergences are regularized by the lifetime of the decaying particle or the total scattering cross section. Also, these regularizations are shown to give the expected helicities of final particles. As an illustration, the density matrix is derived for the weak decay of a polarized muon at rest, µ- → νµ(e-ν¯e), with Lorentz invariant density matrix entries and unitarity upheld at tree level. The electron’s von Neumann entanglement entropy distributions are derived with respect to both the electron’s emission angle and energy. The angular entropy distribution peaks for an electron emitted backward with respect to the muon’s polarization given a minimum volume regularization larger than the cube of the muon’s Compton wavelength. The kinematic entropy distribution is maximal at half the muon’s rest mass energy. These results are similar to the electron’s angular and kinematic decay rate distributions. Both the density matrix and entanglement entropy can be cast in terms of either ratios of areas or volumes.
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