Edge Currents and Vertex Operators for Chern-Simons Gravity

We apply elementary canonical methods for the quantization of 2+1 dimensional gravity, where the dynamics is given by E. Witten's $ISO(2,1)$ Chern-Simons action. As in a previous work, our approach does not involve choice of gauge or clever manipulations of functional integrals. Instead, we just require the Gauss law constraint for gravity to be first class and also to be everywhere differentiable. When the spatial slice is a disc, the gravitational fields can either be unconstrained or constrained at the boundary of the disc. The unconstrained fields correspond to edge currents which carry a representation of the $ISO(2,1)$ Kac-Moody algebra. Unitary representations for such an algebra have been found using the method of induced representations. In the case of constrained fields, we can classify all possible boundary conditions. For several different boundary conditions, the field content of the theory reduces precisely to that of 1+1 dimensional gravity theories. We extend the above formalism to include sources. The sources take into account self- interactions. This is done by punching holes in the disc, and erecting an $ISO(2,1)$ Kac-Moody algebra on the boundary of each hole. If the hole is originally sourceless, a source can be created via the action of a vertex operator $V$. We give an explicit expression for $V$. We shall show that when actingComment: 42 pages, UAHEP 925, SU-4240-508, INFN-NA-IV-92/1

A Monte Carlo study of Inverse Symmetry Breaking

We make a Monte Carlo study of the coupled two-scalar $\lambda\phi^2_1\phi^2_2$ model in four dimensions at finite temperature. We find no trace of Inverse Symmetry Breaking for values of the renormalized parameters for which perturbation theory predicts this phenomenon.Comment: 4 pages, revtex, 3 figures include

Social scarcity and tourist's life satisfaction: An empirical and theoretical analysis

This paper presents the results of an analysis that compared two types of tourists who hold a different view of and interact differently with their surrounding environment. It evidenced that more consumptive and consumer-oriented tourists are normally less happy than those practising more appreciative and sharing-oriented activities. To explain the differential, it offers a theoretical interpretation based on the idea that individual choices are not autonomous and independent, and that aspects like comparisons, observability of possessions and level of competition in the reference group may dampen the effect of various correlates on people's life satisfaction

Novel features of the energy momentum tensor of a Casimir apparatus in a weak gravitational field

The influence of the gravity acceleration on the regularized energy-momentum tensor of the quantized electromagnetic field between two plane parallel conducting plates is derived. A perturbative expansion, to first order in the constant acceleration parameter, of the Green functions involved and of the energy-momentum tensor is derived by means of the covariant geodesic point splitting procedure. The energy-momentum tensor is covariantly conserved and satisfies the expected relation between gauge-breaking and ghost parts.Comment: 8 pages, based on a talk given by Luigi Rosa at the QFEXT07 Conference, Leipzig. Equation (13) and the formulae for rho and energy E stored in the Casimir device have been amended, jointly with related discussio

The Chern-Simons Source as a Conformal Family and Its Vertex Operators

In a previous work, a straightforward canonical approach to the source-free quantum Chern-Simons dynamics was developed. It makes use of neither gauge conditions nor functional integrals and needs only ideas known from QCD and quantum gravity. It gives Witten's conformal edge states in a simple way when the spatial slice is a disc. Here we extend the formalism by including sources as well. The quantum states of a source with a fixed spatial location are shown to be those of a conformal family, a result also discovered first by Witten. The internal states of a source are not thus associated with just a single ray of a Hilbert space. Vertex operators for both abelian and nonabelian sources are constructed. The regularized abelian Wilson line is proved to be a vertex operator. We also argue in favor of a similar nonabelian result. The spin-statistics theorem is established for Chern-Simons dynamics even though the sources are not described by relativistic quantum fields. The proof employs geometrical methods which we find are strikingly transparent and pleasing. It is based on the research of European physicists about ``fields localized on cones.'

Towards a model for the multidimensional analysis of field data

International audienceIntegration of spatial data into multidimensional models leads to the concept of Spatial OLAP (SOLAP). Usually, SOLAP models exploit discrete spatial data. Few works integrate continuous field data into dimensions and measures. In this paper, we provide a multidimensional model that supports measures and dimension as continuous field data, independently of their implementation

Comment on "Quantitative wave-particle duality in multibeam interferometers"

In a recent paper [Phys. Rev. {\bf A64}, 042113 (2001)] S. D\"urr proposed an interesting multibeam generalization of the quantitative formulation of interferometric wave-particle duality, discovered by Englert for two-beam interferometers. The proposed generalization is an inequality that relates a generalized measure of the fringe visibility, to certain measures of the maximum amount of which-way knowledge that can be stored in a which-way detector. We construct an explicit example where, with three beams in a pure state, the scheme proposed by D\"{u}rr leads to the possibility of an ideal which-way detector, that can achieve a better path-discrimination, at the same time as a better fringe visibility. In our opinion, this seems to be in contrast with the intuitive idea of complementarity, as it is implemented in the two-beams case, where an increase in path discrimination always implies a decrease of fringe visibility, if the beams and the detector are in pure states.Comment: 4 pages, 1 encapsulated figure. In press on Phys. Rev.

Designing data warehouses for geographic OLAP querying by using MDA

Data aggregation in Geographic Information Systems (GIS) is a desirable feature, spatial data are integrated in OLAP engines for this purpose. However, the development and operation of those systems is still a complex task due to methodologies followed. There are some ad hoc solutions that deal only with isolated aspects and do not provide developer and analyst with an intuitive, integrated and standard framework for designing all relevant parts. To overcome these problems, we have defined a model driven approach to accomplish Geographic Data Warehouse (GDW) development. Then, we have defined a data model required to implement and query spatial data. Its modeling is defined and implemented by using an extension of UML metamodel and it is also formalized by using OCL language. In addition, the proposal has been verified against a example scenario with sample data sets. For this purpose, we have accomplished a developing tool based on Eclipse platform and MDA standard. The great advantage of this solution is that developers can directly include spatial data at conceptual level, while decision makers can also conceptually make geographic queries without being aware of logical details.This work has been partially supported by the ESPIA project (TIN2007-67078) from the Spanish Ministry of Education and Science and by the QUASIMODO project (PAC08-0157-0668) from the Castilla-La Mancha Ministry of Education and Science (Spain). Octavio Glorio is funded by the University of Alicante under the 11th Latin American grant program

Johnson-Nyquist noise and the Casimir force between real metals at nonzero temperature

It is well known since a long time that all lossy conductors at finite temperature display an electronic noise, the Johnson-Nyquist noise, arising from the thermal agitation of electric charges inside the conductor. The existence of this noise implies that two nearby discharged conductors at finite temperature should repel each other, as a result of the electrodynamic interaction between the Johnson-Nyquist currents in either conductor and the eddy currents they induce in the other. It is suggested that this force is at the origin of the recently discovered large repulsive correction to the thermal Casimir force between two lossy metallic plates. Further support for this physical picture is obtained by studying a simple system of two linear noisy antennas. Using elementary concepts from circuit theory, we show that the repulsive force engendered by the Johnson-Nyquist noise results in the same kind of thermodynamic inconsistencies found in the Casimir problem. We show that all inconsistencies are however resolved if account is taken of capacitive effects associated with the end points of the antennas. Our findings therefore suggest that capacitive effects resulting from the finite size of the plates, may be essential for a resolution of the analogous problems met in the thermal Casimir effect.Comment: 9 pages, 1 encapsulated figure. Contributed to 8th Workshop on Quantum Field Theory Under the Influence of External Conditions (QFEXT07), Leipzig, Germany, 17-21 Sep 200

Focus - Un système OLAP pour l'analyse de données de lutte intégrée : application à la culture de l'olivier

The Agri-Food sector is facing global challenges. The first concerns feeding a world population that in 2050, according to UN projections, will reach 9.3 billion people. The second challenge is the request by consumers for high quality products obtained by more sustainable, safely and clear agri-food cains. The Integrated Pest Management (IPM) could be an important instrument to help farmers to face these challenges. The IPM requires the simultaneous use of different crop protection techniques for the control of pests through an ecological and economic approach. This work explores the possibility to develop a framework that combines the Information and Communication Technologies (ICTs) with the IPM principles, in order to support the farmers in the decisional process, improving environmental and production performances. The proposed ICT tool is On-Line Analytical Processing (OLAP), which allows performing analysis in the domain of time and space verifying for a single farm the respect of the IPM technical specifications.Le secteur agroalimentaire est confronté à des défis mondiaux. Le premier concerne l'alimentation d'une population mondiale qui, selon les prévisions de l'ONU, atteindra 9,3 milliards de personnes en 2050. Le deuxième défi est la demande des consommateurs pour des produits de haute qualité obtenus par des chaînes agroalimentaires plus durables, plus sûres et plus claires. La lutte intégrée (LI) pourrait constituer un instrument important pour aider les agriculteurs à faire face à ces défis. La LI requiert l'utilisation simultanée de différentes techniques de protection des cultures pour la lutte contre les organismes nuisibles par le biais d'une approche écologique et économique. Ce travail explore la possibilité de développer un cadre théorique combinant les technologies des systèmes d'information et de Business Intelligence (BI) avec les principes de la LI, afin d'aider les agriculteurs dans le processus décisionnel pour améliorer les performances environnementales et de production. L'outil BI proposé est un système de traitement analytique en ligne (OLAP), qui permet d'effectuer des analyses spatio-temporelles pour les données de LI