2,630 research outputs found
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
Dark energy, cosmological constant and neutrino mixing
The today estimated value of dark energy can be achieved by the vacuum
condensate induced by neutrino mixing phenomenon. Such a tiny value is
recovered for a cut-off of the order of Planck scale and it is linked to the
sub eV neutrino mass scale. Contributions to dark energy from auxiliary fields
or mechanisms are not necessary in this approach.Comment: 10 pages, 2 figure
Quantization of scalar fields in curved background, deformed Hopf algebra and entanglement
A suitable deformation of the Hopf algebra of the creation and annihilation
operators for a complex scalar field, initially quantized in Minkowski
space--time, induces the canonical quantization of the same field in a generic
gravitational background. The deformation parameter q turns out to be related
to the gravitational field. The entanglement of the quantum vacuum appears to
be robust against interaction with the environment.Comment: 4 pages, to appear in Proceedings of the XXIV International
Colloquium on Group Theoretical Methods in Physics, Paris, 14-21 July 200
Interoperable services based on activity monitoring in ambient assisted living environments
Ambient Assisted Living (AAL) is considered as the main technological solution that will enable the aged and people in recovery to maintain their independence and a consequent high quality of life for a longer period of time than would otherwise be the case. This goal is achieved by monitoring human’s activities and deploying the appropriate collection of services to set environmental features and satisfy user preferences in a given context. However, both human monitoring and services deployment are particularly hard to accomplish due to the uncertainty and ambiguity characterising human actions, and heterogeneity of hardware devices composed in an AAL system. This research addresses both the aforementioned challenges by introducing 1) an innovative system, based on Self Organising Feature Map (SOFM), for automatically classifying the resting location of a moving object in an indoor environment and 2) a strategy able to generate context-aware based Fuzzy Markup Language (FML) services in order to maximize the users’ comfort and hardware interoperability level. The overall system runs on a distributed embedded platform with a specialised ceiling- mounted video sensor for intelligent activity monitoring. The system has the ability to learn resting locations, to measure overall activity levels, to detect specific events such as potential falls and to deploy the right sequence of fuzzy services modelled through FML for supporting people in that particular context. Experimental results show less than 20% classification error in monitoring human activities and providing the right set of services, showing the robustness of our approach over others in literature with minimal power consumption
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
QUANTUM DISSIPATION AND QUANTUM NOISE
We derive the exact action for a damped mechanical system ( and the special
case of the linear oscillator) from the path integral formulation of the
quantum Brownian motion problem developed by Schwinger and by Feynman and
Vernon. The doubling of the phase-space degrees of freedom for dissipative
systems and thermal field theories is discussed and the initial values of the
doubled variables are related to quantum noise effects.Comment: This is a Tex file; To be published in Annals of Phys. (N.Y.) 238,
200 (1995
Green's Functions for Neutrino Mixing
The Green's function formalism for neutrino mixing is presented and the exact
oscillation formula is obtained. The usual Pontecorvo formula is recovered in
the relativistic limit.Comment: 4 pages, LaTeX (need sprocl.sty). To appear in the Proceedings of the
6th International Symposium on Particles, Strings and Cosmology (PASCOS 98),
Boston, 22-27 March 199
- …