51 research outputs found
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
Nonassociative strict deformation quantization of C*-algebras and nonassociative torus bundles
In this paper, we initiate the study of nonassociative strict deformation
quantization of C*-algebras with a torus action. We shall also present a
definition of nonassociative principal torus bundles, and give a classification
of these as nonassociative strict deformation quantization of ordinary
principal torus bundles. We then relate this to T-duality of principal torus
bundles with -flux. We also show that the Octonions fit nicely into our
theory.Comment: 15 pages, latex2e, exposition improved, to appear in LM
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
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
Quantisation of twistor theory by cocycle twist
We present the main ingredients of twistor theory leading up to and including
the Penrose-Ward transform in a coordinate algebra form which we can then
`quantise' by means of a functorial cocycle twist. The quantum algebras for the
conformal group, twistor space CP^3, compactified Minkowski space CMh and the
twistor correspondence space are obtained along with their canonical quantum
differential calculi, both in a local form and in a global *-algebra
formulation which even in the classical commutative case provides a useful
alternative to the formulation in terms of projective varieties. We outline how
the Penrose-Ward transform then quantises. As an example, we show that the
pull-back of the tautological bundle on CMh pulls back to the basic instanton
on S^4\subset CMh and that this observation quantises to obtain the
Connes-Landi instanton on \theta-deformed S^4 as the pull-back of the
tautological bundle on our \theta-deformed CMh. We likewise quantise the
fibration CP^3--> S^4 and use it to construct the bundle on \theta-deformed
CP^3 that maps over under the transform to the \theta-deformed instanton.Comment: 68 pages 0 figures. Significant revision now has detailed formulae
for classical and quantum CP^
T-duality for principal torus bundles
In this paper we study T-duality for principal torus bundles with H-flux. We
identify a subset of fluxes which are T-dualizable, and compute both the dual
torus bundle as well as the dual H-flux. We briefly discuss the generalized
Gysin sequence behind this construction and provide examples both of non
T-dualizable and of T-dualizable H-fluxes.Comment: 9 pages, typos removed and minor corrections mad
Fermion Quasi-Spherical Harmonics
Spherical Harmonics, , are derived and presented (in a
Table) for half-odd-integer values of and . These functions are
eigenfunctions of and written as differential operators in the
spherical-polar angles, and . The Fermion Spherical Harmonics
are a new, scalar and angular-coordinate-dependent representation of fermion
spin angular momentum. They have symmetry in the angle , and hence
are not single-valued functions on the Euclidean unit sphere; they are
double-valued functions on the sphere, or alternatively are interpreted as
having a double-sphere as their domain.Comment: 16 pages, 2 Tables. Submitted to J.Phys.
Quantizing the damped harmonic oscillator
We consider the Fermi quantization of the classical damped harmonic
oscillator (dho). In past work on the subject, authors double the phase space
of the dho in order to close the system at each moment in time. For an
infinite-dimensional phase space, this method requires one to construct a
representation of the CAR algebra for each time. We show that unitary dilation
of the contraction semigroup governing the dynamics of the system is a logical
extension of the doubling procedure, and it allows one to avoid the
mathematical difficulties encountered with the previous method.Comment: 4 pages, no figure
Dark energy and particle mixing
We show that the vacuum condensate due to particle mixing is responsible of a
dynamically evolving dark energy. In particular, we show that values of the
adiabatic index close to -1 for vacuum condensates of neutrinos and quarks
imply, at the present epoch, contributions to the vacuum energy compatible with
the estimated upper bound on the dark energy.Comment: 11 page
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
- âŠ