49 research outputs found
What are the Building Blocks of Our Universe?
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
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
We consider a four-dimensional space-time supplemented by two discrete points
assigned to a 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
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
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
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
Metric Theory of Gravity with Torsion in an Extra Dimension
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
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