4,764 research outputs found
Scalar and tensorial topological matter coupled to (2+1)-dimensional gravity:A.Classical theory and global charges
We consider the coupling of scalar topological matter to (2+1)-dimensional
gravity. The matter fields consist of a 0-form scalar field and a 2-form tensor
field. We carry out a canonical analysis of the classical theory, investigating
its sectors and solutions. We show that the model admits both BTZ-like
black-hole solutions and homogeneous/inhomogeneous FRW cosmological
solutions.We also investigate the global charges associated with the model and
show that the algebra of charges is the extension of the Kac-Moody algebra for
the field-rigid gauge charges, and the Virasoro algebrafor the diffeomorphism
charges. Finally, we show that the model can be written as a generalized
Chern-Simons theory, opening the perspective for its formulation as a
generalized higher gauge theory.Comment: 40 page
Effect of winding harmonics on the asynchronous torque of a single-phase line start permanant-magnet motor
This paper presents an analytical method for calculating the effect of winding harmonics on the asynchronous torque of a single-phase line-start permanent-magnet motor. The method is an extension of earlier work, which combines symmetrical-component analysis with dq-axis theory to model the various components of forward and backward rotating fields. The effect of individual winding harmonics is brought out both theoretically and experimentally, by comparing calculated and measured torque/speed characteristics for a series of six motors with different distributions of turns in both the main and auxiliary windings
Entropy and specific heat for open systems in steady states
The fundamental assumption of statistical mechanics is that the system is
equally likely in any of the accessible microstates. Based on this assumption,
the Boltzmann distribution is derived and the full theory of statistical
thermodynamics can be built. In this paper, we show that the Boltzmann
distribution in general can not describe the steady state of open system. Based
on the effective Hamiltonian approach, we calculate the specific heat, the free
energy and the entropy for an open system in steady states. Examples are
illustrated and discussed.Comment: 4 pages, 7 figure
Canonical analysis of the BCEA topological matter model coupled to gravitation in (2+1) dimensions
We consider a topological field theory derived from the Chern - Simons action
in (2+1) dimensions with the I(ISO(2,1)) group,and we investigate in detail the
canonical structure of this theory.Originally developed as a topological theory
of Einstein gravity minimally coupled to topological matter fields in (2+1)
dimensions, it admits a BTZ black-hole solutions, and can be generalized to
arbitrary dimensions.In this paper, we further study the canonical structure of
the theory in (2+1) dimensions, by identifying all the distinct gauge
equivalence classes of solutions as they result from holonomy considerations.
The equivalence classes are discussed in detail, and examples of solutions
representative of each class are constructed or identified.Comment: 17 pages, no figure
Modelling the Pan-Spectral Energy Distributions of Starburst & Active Galaxies
We present results of a self-consistent model of the spectral energy
distribution (SED) of starburst galaxies. Two parameters control the IR SED,
the mean pressure in the ISM and the destruction timescale of molecular clouds.
Adding a simplified AGN spectrum provides mixing lines on IRAS color : color
diagrams. This reproduces the observed colors of both AGNs and starbursts.Comment: Poster Paper for IAU 222: The Interplay among Black Holes, Stars and
ISM in Galactic Nucle
Macroscopically local correlations can violate information causality
Although quantum mechanics is a very successful theory, its foundations are
still a subject of intense debate. One of the main problems is the fact that
quantum mechanics is based on abstract mathematical axioms, rather than on
physical principles. Quantum information theory has recently provided new ideas
from which one could obtain physical axioms constraining the resulting
statistics one can obtain in experiments. Information causality and macroscopic
locality are two principles recently proposed to solve this problem. However
none of them were proven to define the set of correlations one can observe. In
this paper, we present an extension of information causality and study its
consequences. It is shown that the two above-mentioned principles are
inequivalent: if the correlations allowed by nature were the ones satisfying
macroscopic locality, information causality would be violated. This gives more
confidence in information causality as a physical principle defining the
possible correlation allowed by nature.Comment: are welcome. 6 pages, 4 figs. This is the originally submitted
version. The published version contains some bounds on quantum realizations
of d2dd isotropic boxes (table 1), found by T. Vertesi, who kindly shared
them with u
A QoE Model for Mulsemedia TV in a Smart Home Environment
The provision to the users of realistic media contents is one of the main goals of future media services. The sense of reality perceived by the user can be enhanced by adding various sensorial effects to the conventional audio-visual content, through the stimulation of the five senses stimulation (sight, hearing, touch, smell and taste), the so-called multi-sensorial media (mulsemedia). To deliver the additional effects within a smart home (SH) environment, custom devices (e.g., air conditioning, lights) providing opportune smart features, are preferred to ad-hoc devices, often deployed in a specific context such as for example in gaming consoles. In the present study, a prototype for a mulsemedia TV application, implemented in a real smart home scenario, allowed the authors to assess the user's Quality of Experience (QoE) through test measurement campaign. The impact of specific sensory effects (i.e., light, airflow, vibration) on the user experience regarding the enhancement of sense of reality, annoyance, and intensity of the effects was investigated through subjective assessment. The need for multi sensorial QoE models is an important challenge for future research in this field, considering the time and cost of subjective quality assessments. Therefore, based on the subjective assessment results, this paper instantiates and validates a parametric QoE model for multi-sensorial TV in a SH scenario which indicates the relationship between the quality of audiovisual contents and user-perceived QoE for sensory effects applications
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