377 research outputs found
Axi-Dilaton Gravity in D \geq 4 Dimensional Space-Times with Torsion
We study models of axi-dilaton gravity in space-time geometries with torsion.
We discuss conformal re-scaling rules in both Riemannian and non-Riemannian
formulations. We give static, spherically symmetric solutions and examine their
singularity structure
Monopole equations on 8-manifolds with Spin(7) holonomy
We construct a consistent set of monopole equations on eight-manifolds with
Spin(7) holonomy. These equations are elliptic and admit non-trivial solutions
including all the 4-dimensional Seiberg-Witten solutions as a special case.Comment: 14 pages, LATEX (No figures
The Geometry of Self-dual 2-forms
We show that self-dual 2-forms in 2n dimensional spaces determine a
dimensional manifold and the dimension of the maximal linear
subspaces of is equal to the (Radon-Hurwitz) number of linearly
independent vector fields on the sphere . We provide a direct proof
that for odd has only one-dimensional linear submanifolds.
We exhibit dimensional subspaces in dimensions which are multiples of
, for . In particular, we demonstrate that the seven dimensional
linear subspaces of also include among many other interesting
classes of self-dual 2-forms, the self-dual 2-forms of Corrigan, Devchand,
Fairlie and Nuyts and a representation of
given by octonionic multiplication. We discuss the relation of the linear
subspaces with the representations of Clifford algebras.Comment: Latex, 15 page
Dirac equation in spacetimes with torsion and non-metricity
Dirac equation is written in a non-Riemannian spacetime with torsion and
non-metricity by lifting the connection from the tangent bundle to the spinor
bundle over spacetime. Foldy-Wouthuysen transformation of the Dirac equation in
a Schwarzschild background spacetime is considered and it is shown that both
the torsion and non-metricity couples to the momentum and spin of a massive,
spinning particle. However, the effects are small to be observationally
significant.Comment: 12 pages LATEX file, no figures, to appear in Int. J. Mod. Phys.
String-Inspired Chern-Simons Modified Gravity In 4-Dimensions
Chern-Simons modified gravity models in 4-dimensions are shown to be special
cases of low energy effective string models to first order in the string
constant.Comment: To appear in the European Physics Journal
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