47 research outputs found

    What are the Building Blocks of Our Universe?

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    We are told that we are living in a Golden Age of Astronomy. Cosmological Parameters are found with un precedented accuracy. Yet, the known form of matter forms only a small fraction of the total energy density of the universe. Also, a mysterious dark energy dominates the universe and causes acceleration in the rate of expansion.Comment: To be published in the Proceedings of the Interantional Conference on COSMOLOGY;Facts and Problems (College de France, Paris, June 8-11, 2004

    A Discretized Version of Kaluza-Klein Theory with Torsion and Massive Fields

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    We consider an internal space of two discrete points in the fifth dimension of the Kaluza-Klein theory by using the formalism of noncommutative geometry developed in a previous paper \cite{VIWA} of a spacetime supplemented by two discrete points. With the nonvanishing internal torsion 2-form there are no constraints implied on the vielbeins. The theory contains a pair of tensor, a pair of vector and a pair of scalar fields. Using the generalized Cartan structure equation we are able not only to determine uniquely the hermitian and metric compatible connection 1-forms, but also the nonvanishing internal torsion 2-form in terms of vielbeins. The resulting action has a rich and complex structure, a particular feature being the existence of massive modes. Thus the nonvanishing internal torsion generates a Kaluza-Klein type model with zero and massive modes.Comment: 24 page

    Noncommutative Geometry and a Discretized Version of Kaluza-Klein Theory with a Finite Field Content

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    We consider a four-dimensional space-time supplemented by two discrete points assigned to a Z2Z_2 algebraic structure and develop the formalism of noncommutative geometry. By setting up a generalised vielbein, we study the metric structure. Metric compatible torsion free connection defines a unique finite field content in the model and leads to a discretized version of Kaluza-Klein theory. We study some special cases of this model that illustrate the rich and complex structure with massive modes and the possible presence of a cosmological constant.Comment: 21 pages, LATEX fil

    Baryons and Mesons with Beauty

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    Recent experimental findings of several mesons and baryons with "beauty" and "charm" as flavors remind us of the days when strangeness was discovered, and how its inclusion led to SU(3)-flavor symmetry with enormous success in the classification of the "proliferated" states into SU(3) multiplets. One of the key elements was the successful application of the first order perturbation in symmetry breaking, albeit what then appeared to be huge mass differences, and the prediction of new states that were confirmed by experiments. In this note, we venture into the past and, applying the same techniques, predict some new "beauty-" and "charm-" flavored hadrons. If these new states are confirmed experimentally, it may provide a useful phenomenological model for classifying numerous states that are found to be in the PDG data and could invite further theoretical challenges towards our understanding of symmetry breaking.Comment: 9 pages, 5 figures, plain Late

    Black holes with magnetic charge and quantized mass

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    We examine the issue of magnetic charge quantization in the presence of black holes. It is pointed out that quantization of magnetic charge can lead to the mass quantization for magnetically charged black holes. We also discuss some implications for the experimental searches of magnetically charged black holes.Comment: RevTeX, 11 pages, Invited paper for the first editorial volume of the book series "Contemporary Fundamental Physics" by the Nova Science Publisher

    Matter Fields in Curved Space-Time

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    We study the geometry of a two-sheeted space-time within the framework of non-commutative geometry. As a prelude to the Standard Model in curved space-time, we present a model of a left- and a right- chiral field living on the two sheeted-space time and construct the action functionals that describe their interactions.Comment: 14 pages LaTeX, to appear in AIP proceedings of MRST Conference at Rochester NY, May 200

    Book Reviews

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    Metric Theory of Gravity with Torsion in an Extra Dimension

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    We consider a theory of gravity with a hidden extra dimension and metric-dependent torsion. A set of physically motivated constraints are imposed on the geometry so that the torsion stays confined to the extra dimension and the extra dimension stays hidden at the level of four-dimensional geodesic motion. At the kinematic level, the theory maps onto general relativity, but the dynamical field equations that follow from the action principle deviate markedly from the standard Einstein equations. We study static spherically symmetric vacuum solutions and homogeneous-isotropic cosmological solutions that emerge from the field equations. In both cases, we find solutions of significant physical interest. Most notably, we find positive mass solutions with naked singularity that match the well-known Schwarzschild solution at large distances but lack an event horizon. In the cosmological context, we find an oscillatory scenario, in contrast to the inevitable singular big bang of the standard cosmology

    Metric Theory of Gravity with Torsion in an Extra Dimension

    Get PDF
    We consider a theory of gravity with a hidden extra dimension and metric-dependent torsion. A set of physically motivated constraints are imposed on the geometry so that the torsion stays confined to the extra dimension and the extra dimension stays hidden at the level of four-dimensional geodesic motion. At the kinematic level, the theory maps onto general relativity, but the dynamical field equations that follow from the action principle deviate markedly from the standard Einstein equations. We study static spherically symmetric vacuum solutions and homogeneous-isotropic cosmological solutions that emerge from the field equations. In both cases, we find solutions of significant physical interest. Most notably, we find positive mass solutions with naked singularity that match the well-known Schwarzschild solution at large distances but lack an event horizon. In the cosmological context, we find an oscillatory scenario, in contrast to the inevitable singular big bang of the standard cosmology
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