280 research outputs found

### Physical flavor neutrino states

The problem of representation for flavor states of mixed neutrinos is
discussed. By resorting to recent results, it is shown that a specific
representation exists in which a number of conceptual problems are resolved.
Phenomenological consequences of our analysis are explored.Comment: Presented at 5th International Workshop DICE2010: Space-Time-Matter -
Current Issues in Quantum Mechanics and Beyon

### Mixing and oscillations of neutral particles in Quantum Field Theory

We study the mixing of neutral particles in Quantum Field Theory: neutral
boson field and Majorana field are treated in the case of mixing among two
generations. We derive the orthogonality of flavor and mass representations and
show how to consistently calculate oscillation formulas, which agree with
previous results for charged fields and exhibit corrections with respect to the
usual quantum mechanical expressions.Comment: 8 pages, revised versio

### Lepton charge and neutrino mixing in pion decay processes

We consider neutrino mixing and oscillations in quantum field theory and
compute the neutrino lepton charge in decay processes where neutrinos are
generated. We also discuss the proper definition of flavor charge and states
and clarify the issues of the possibility of different mass parameters in field
mixing.Comment: 13 page

### Fermion mixing in quasi-free states

Quantum field theoretic treatments of fermion oscillations are typically
restricted to calculations in Fock space. In this letter we extend the
oscillation formulae to include more general quasi-free states, and also
consider the case when the mixing is not unitary.Comment: 10 pages, Plain Te

### Neutrino mixing contribution to the cosmological constant

We show that the non-perturbative vacuum structure associated with neutrino
mixing leads to a non-zero contribution to the value of the cosmological
constant. Such a contribution comes from the specific nature of the mixing
phenomenon. Its origin is completely different from the one of the ordinary
contribution of a massive spinor field. We estimate this neutrino mixing
contribution by using the natural cut--off appearing in the quantum field
theory formalism for neutrino mixing and oscillation.Comment: 7 page

### Quantization, group contraction and zero point energy

We study algebraic structures underlying 't Hooft's construction relating
classical systems with the quantum harmonic oscillator. The role of group
contraction is discussed. We propose the use of SU(1,1) for two reasons:
because of the isomorphism between its representation Hilbert space and that of
the harmonic oscillator and because zero point energy is implied by the
representation structure. Finally, we also comment on the relation between
dissipation and quantization.Comment: 6 pages, 3 figure

### Group theoretical aspects of neutrino mixing in Quantum Field Theory

By resorting to recent results on the Quantum Field Theory of mixed
particles, we discuss some aspects of three flavor neutrino mixing. Particular
emphasis is given to the related algebraic structures and their deformation in
the presence of CP violation. A novel geometric phase related to CP violation
is introduced.Comment: 10 pages, 2 figures. Presented at the XII International Baksan School
"Particles and Cosmology", Baksan Valley, Kabardino-Balkaria, Russian
Federation - April 21 - 26, 200

### Understanding flavor mixing in Quantum Field Theory

We report on recent results showing that a rich non-perturbative vacuum
structure is associated with flavor mixing in Quantum Field Theory.
We treat explicitly the case of mixing among three generations of Dirac
fermions.
Exact oscillation formulas are presented exhibiting new features with respect
to the usual ones. CP and T violation are also discussed.Comment: 9 pages. Presented at the "International Conference on Flavor
Physics", Zhang-Jia-Jie, China, May 31 - June 6 200

### Macroscopic Observables Detecting Genuine Multipartite Entanglement and Partial Inseparability in Many-Body Systems

We show a general approach for detecting genuine multipartite entanglement
(GME) and partial inseparability in many-body-systems by means of macroscopic
observables (such as the energy) only. We show that the obtained criteria, the
"GME gap" and "the k-entanglement gap", detect large areas of genuine
multipartite entanglement and partial entanglement in typical many body states,
which are not detected by other criteria. As genuine multipartite entanglement
is a necessary property for several quantum information theoretic applications
such as e.g. secret sharing or certain kinds of quantum computation, our
methods can be used to select or design appropriate condensed matter systems.Comment: 4 pages, 3 figures, published version, title extende

### Neutrino oscillations from relativistic flavor currents

By resorting to recent results on the relativistic currents for mixed
(flavor) fields, we calculate a space-time dependent neutrino oscillation
formula in Quantum Field Theory. Our formulation provides an alternative to
existing approaches for the derivation of space dependent oscillation formulas
and it also accounts for the corrections due to the non-trivial nature of the
flavor vacuum. By exploring different limits of our formula, we recover already
known results. We study in detail the case of one-dimensional propagation with
gaussian wavepackets both in the relativistic and in the non-relativistic
regions: in the last case, numerical evaluations of our result show significant
deviations from the standard formula.Comment: 16 pages, 4 figures, RevTe

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