Dynamics of disentanglement, density matrix, and coherence in neutrino oscillations

Journal Article · Thu Jul 01 04:00:00 EDT 2010 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.82.013006· OSTI ID:21410017

Jun, Wu; Boyanovsky, Daniel ^[1]; Hutasoit, Jimmy A; Holman, Richard ^[2]

---

1. Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)
2. Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

In charged current weak interaction processes, neutrinos are produced in an entangled state with the charged lepton. This correlated state is disentangled by the measurement of the charged lepton in a detector at the production site. We study the dynamical aspects of disentanglement, propagation, and detection, in particular, the conditions under which the disentangled state is a coherent superposition of mass eigenstates. The appearance and disappearance far-detection processes are described from the time evolution of this disentangled 'collapsed' state. The familiar quantum mechanical interpretation and factorization of the detection rate emerges when the quantum state is disentangled on time scales much shorter than the inverse oscillation frequency, in which case the final detection rate factorizes in terms of the usual quantum mechanical transition probability provided the final density of states is insensitive to the neutrino energy difference. We suggest possible corrections for short-baseline experiments. If the charged lepton is unobserved, neutrino oscillations and coherence are described in terms of a reduced density matrix obtained by tracing out an unobserved charged lepton. The diagonal elements in the mass basis describe the production of mass eigenstates whereas the off-diagonal ones provide a measure of coherence. It is shown that coherences are of the same order of the diagonal terms on time scales up to the inverse oscillation frequency, beyond which the coherences oscillate as a result of the interference between mass eigenstates.

• OSTI ID: 21410017
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 1 Vol. 82; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGEBRAIC CURRENTS
BASIC INTERACTIONS
CHARGED CURRENTS
CORRECTIONS
CURRENTS
DENSITY
DENSITY MATRIX
DETECTION
EIGENSTATES
ELEMENTARY PARTICLES
FACTORIZATION
FERMIONS
INTERACTIONS
INTERFERENCE
LEPTONS
MASS
MASSLESS PARTICLES
MATRICES
MECHANICS
NEUTRINO OSCILLATION
NEUTRINOS
OSCILLATIONS
PHYSICAL PROPERTIES
PROBABILITY
QUANTUM ENTANGLEMENT
QUANTUM MECHANICS
WEAK INTERACTIONS