191 research outputs found
Vacuum Bubbles Nucleation and Dark Matter Production through Gauge Symmetry Rearrangement
Modern particle physics and cosmology support the idea that a background of
invisible material pervades the whole universe, and identify in the cosmic
vacuum the ultimate source of matter-energy, both seen and unseen. Within the
framework of the theory of fundamental relativistic membranes, we suggest a
self-consistent, vacuum energy-driven mechanism for dark matter creation
through gauge symmetry rearrangement.Comment: 22pages, RevTeX, no figures; accepted for publication in Phys.Rev.
String Representation of Quantum Loops
We recover a general representation for the quantum state of a relativistic
closed line (loop) in terms of string degrees of freedom.The general form of
the loop functional splits into the product of the Eguchi functional, encoding
the holographic quantum dynamics, times the Polyakov path integral, taking into
account the full Bulk dynamics, times a loop effective action, which is needed
to renormalize boundary ultraviolet divergences. The Polyakov string action is
derived as an effective actionfrom a phase space,covariant,Schild action, by
functionally integrating out the world-sheet coordinates.The area coordinates
description of the boundary quantum dynamics, is shown to be induced by the
``zero mode'' of the bulk quantum fluctuations. Finally, we briefly comment
about a ``unified, fully covariant'' description of points, loops and strings
in terms of Matrix Coordinates.Comment: 16 Pages, RevTeX, no figure
Postmodern String Theory: Stochastic Formulation
In this paper we study the dynamics of a statistical ensemble of strings,
building on a recently proposed gauge theory of the string geodesic field. We
show that this stochastic approach is equivalent to the Carath\'eodory
formulation of the Nambu-Goto action, supplemented by an averaging procedure
over the family of classical string world-sheets which are solutions of the
equation of motion. In this new framework, the string geodesic field is
reinterpreted as the Gibbs current density associated with the string
statistical ensemble. Next, we show that the classical field equations derived
from the string gauge action, can be obtained as the semi-classical limit of
the string functional wave equation. For closed strings, the wave equation
itself is completely analogous to the Wheeler-DeWitt equation used in quantum
cosmology. Thus, in the string case, the wave function has support on the space
of all possible spatial loop configurations. Finally, we show that the string
distribution induces a multi-phase, or {\it cellular} structure on the
spacetime manifold characterized by domains with a purely Riemannian geometry
separated by domain walls over which there exists a predominantly Weyl
geometry.Comment: 24pages, ReVTe
On the equivalence between topologically and non-topologically massive abelian gauge theories
We analyse the equivalence between topologically massive gauge theory (TMGT)
and different formulations of non-topologically massive gauge theories (NTMGTs)
in the canonical approach. The different NTMGTs studied are St\"uckelberg
formulation of (A) a first order formulation involving one and two form fields,
(B) Proca theory, and (C) massive Kalb-Ramond theory. We first quantise these
reducible gauge systems by using the phase space extension procedure and using
it, identify the phase space variables of NTMGTs which are equivalent to the
canonical variables of TMGT and show that under this the Hamiltonian also get
mapped. Interestingly it is found that the different NTMGTs are equivalent to
different formulations of TMGTs which differ only by a total divergence term.
We also provide covariant mappings between the fields in TMGT to NTMGTs at the
level of correlation function.Comment: One reference added and a typos corrected. 15 pages, To appear in
Mod. Phys. Lett.
Gauge Theory of the String Geodesic Field
A relativistic string is usually represented by the Nambu-Goto action in
terms of the extremal area of a 2-dimensional timelike submanifold of Minkowski
space. Alternatively, a family of classical solutions of the string equation of
motion can be globally described in terms of the associated geodesic field. In
this paper we propose a new gauge theory for the geodesic field of closed and
open strings. Our approach solves the technical and conceptual problems
affecting previous attempts to describe strings in terms of local field
variables. The connection between the geodesic field, the string current and
the Kalb-Ramond gauge potential is discussed and clarified. A non-abelian
generalization and the generally covariant form of the model are also
discussed.Comment: 38 pages, PHYZZX, UTS-DFT-92-2
Hausdorff dimension of a quantum string
In the path integral formulation of quantum mechanics, Feynman and Hibbs
noted that the trajectory of a particle is continuous but nowhere
differentiable. We extend this result to the quantum mechanical path of a
relativistic string and find that the ``trajectory'', in this case, is a
fractal surface with Hausdorff dimension three. Depending on the resolution of
the detecting apparatus, the extra dimension is perceived as ``fuzziness'' of
the string world-surface. We give an interpretation of this phenomenon in terms
of a new form of the uncertainty principle for strings, and study the
transition from the smooth to the fractal phase.Comment: 18 pages, non figures, ReVTeX 3.0, in print on Phys.Rev.
Higher Derivative Gravity and Torsion from the Geometry of C-spaces
We start from a new theory (discussed earlier) in which the arena for physics
is not spacetime, but its straightforward extension-the so called Clifford
space (-space), a manifold of points, lines, areas, etc..; physical
quantities are Clifford algebra valued objects, called polyvectors. This
provides a natural framework for description of supersymmetry, since spinors
are just left or right minimal ideals of Clifford algebra. The geometry of
curved -space is investigated. It is shown that the curvature in -space
contains higher orders of the curvature in the underlying ordinary space. A
-space is parametrized not only by 1-vector coordinates but also by
the 2-vector coordinates , 3-vector coordinates , etc., called also {\it holographic coordinates}, since they
describe the holographic projections of 1-lines, 2-loops, 3-loops, etc., onto
the coordinate planes. A remarkable relation between the "area" derivative \p/
\p \sigma^{\mu \nu} and the curvature and torsion is found: if a scalar valued
quantity depends on the coordinates this indicates the
presence of torsion, and if a vector valued quantity depends so, this implies
non vanishing curvature. We argue that such a deeper understanding of the
-space geometry is a prerequisite for a further development of this new
theory which in our opinion will lead us towards a natural and elegant
formulation of -theory.Comment: 19 pages; A section describing the main physical implications of
C-space is added, and the rest of the text is modified accordingl
Spin Gauge Theory of Gravity in Clifford Space
A theory in which 16-dimensional curved Clifford space (C-space) provides a
realization of Kaluza-Klein theory is investigated. No extra dimensions of
spacetime are needed: "extra dimensions" are in C-space. We explore the spin
gauge theory in C-space and show that the generalized spin connection contains
the usual 4-dimensional gravity and Yang-Mills fields of the U(1)xSU(2)xSU(3)
gauge group. The representation space for the latter group is provided by
16-component generalized spinors composed of four usual 4-component spinors,
defined geometrically as the members of four independent minimal left ideals of
Clifford algebra.Comment: 9 pages, talk presented at the QG05 conference, 12-16 September 2005,
Cala Gonone, Ital
Instanton effects and linear-chiral duality
We discuss duality between the linear and chiral dilaton formulations, in the
presence of super-Yang-Mills instanton corrections to the effective action. In
contrast to previous work on the subject, our approach appeals directly to
explicit instanton calculations and does not rely on the introduction of an
auxiliary Veneziano-Yankielowicz superfield. We discuss duality in the case of
an axion that has a periodic scalar potential, and find that the bosonic fields
of the dual linear multiplet have a modified interpretation. We note that
symmetries of the axion potential manifest themselves as symmetries of the
equations of motion for the linear multiplet. We also make some brief remarks
regarding dilaton stabilization. We point out that corrections recently studied
by Dijkgraaf and Vafa can be used to stabilize the axion in the case of a
single super-Yang-Mills condensate.Comment: 1+18 pages, 1 figure, comments and references adde
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