144 research outputs found
Locally Anisotropic Wormholes and Flux Tubes in 5D Gravity
In this article we examine a class of wormhole and flux tube like solutions
to 5D vacuum Einstein equations. These solutions possess generic local
anisotropy, and their local isotropic limit is shown to be conformally
equivalent to the spherically symmetric 5D solutions of gr-qc/9807086. The
anisotropic solutions investigated here have two physically distinct
signatures: First, they can give rise to angular-dependent, anisotropic
``electromagnetic'' interactions. Second, they can result in a gravitational
running of the ``electric'' and ``magnetic'' charges of the solutions. This
gravitational running of the electromagnetic charges is linear rather than
logarithmic, and could thus serve as an indirect signal for the presence of
higher dimensions. The local anisotropy of these solutions is modeled using the
technique of anholonomic frames with respect to which the metrics are
diagonalized. If holonomic coordinates frames were used then such metrics would
have off-diagonal components.Comment: 14 pages, revtex, references added, extra section added giving
physical motivation for the solutions. To be published in PL
Locally Anisotropic Structures and Nonlinear Connections in Einstein and Gauge Gravity
We analyze local anisotropies induced by anholonomic frames and associated
nonlinear connections in general relativity and extensions to affine Poincare
and de Sitter gauge gravity and different types of Kaluza-Klein theories. We
construct some new classes of cosmological solutions of gravitational field
equations describing Friedmann-Robertson-Walker like universes with rotation
(ellongated and flattened) ellipsoidal or torus symmetry.Comment: 37 page
Off-Diagonal Deformations of Kerr Metrics and Black Ellipsoids in Heterotic Supergravity
Geometric methods for constructing exact solutions of motion equations with
first order corrections to the heterotic supergravity action
implying a non-trivial Yang-Mills sector and six dimensional, 6-d,
almost-K\"ahler internal spaces are studied. In 10-d spacetimes, general
parametrizations for generic off-diagonal metrics, nonlinear and linear
connections and matter sources, when the equations of motion decouple in very
general forms are considered. This allows us to construct a variety of exact
solutions when the coefficients of fundamental geometric/physical objects
depend on all higher dimensional spacetime coordinates via corresponding
classes of generating and integration functions, generalized effective sources
and integration constants. Such generalized solutions are determined by generic
off-diagonal metrics and nonlinear and/or linear connections. In particular, as
configurations which are warped/compactified to lower dimensions and for
Levi-Civita connections. The corresponding metrics can have (non) Killing
and/or Lie algebra symmetries and/or describe (1+2)-d and/or (1+3)-d domain
wall configurations, with possible warping nearly almost-K\"ahler manifolds,
with gravitational and gauge instantons for nonlinear vacuum configurations and
effective polarizations of cosmological and interaction constants encoding
string gravity effects. A series of examples of exact solutions describing
generic off-diagonal supergravity modifications to black hole/ ellipsoid and
solitonic configurations are provided and analyzed. We prove that it is
possible to reproduce the Kerr and other type black solutions in general
relativity (with certain types of string corrections) in 4-d and to generalize
the solutions to non-vacuum configurations in (super) gravity/ string theories.Comment: latex2e, 44 pages with table of content, v2 accepted to EJPC with
minor typos modifications requested by editor and referee and up-dated
reference
Fractional Dynamics from Einstein Gravity, General Solutions, and Black Holes
We study the fractional gravity for spacetimes with non-integer dimensions.
Our constructions are based on a geometric formalism with the fractional Caputo
derivative and integral calculus adapted to nonolonomic distributions. This
allows us to define a fractional spacetime geometry with fundamental
geometric/physical objects and a generalized tensor calculus all being similar
to respective integer dimension constructions. Such models of fractional
gravity mimic the Einstein gravity theory and various Lagrange-Finsler and
Hamilton-Cartan generalizations in nonholonomic variables. The approach
suggests a number of new implications for gravity and matter field theories
with singular, stochastic, kinetic, fractal, memory etc processes. We prove
that the fractional gravitational field equations can be integrated in very
general forms following the anholonomic deformation method for constructing
exact solutions. Finally, we study some examples of fractional black hole
solutions, fractional ellipsoid gravitational configurations and imbedding of
such objects in fractional solitonic backgrounds.Comment: latex2e, 11pt, 40 pages with table of conten
Finsler Branes and Quantum Gravity Phenomenology with Lorentz Symmetry Violations
A consistent theory of quantum gravity (QG) at Planck scale almost sure
contains manifestations of Lorentz local symmetry violations (LV) which may be
detected at observable scales. This can be effectively described and classified
by models with nonlinear dispersions and related Finsler metrics and
fundamental geometric objects (nonlinear and linear connections) depending on
velocity/ momentum variables. We prove that the trapping brane mechanism
provides an accurate description of gravitational and matter field phenomena
with LV over a wide range of distance scales and recovering in a systematic way
the general relativity (GR) and local Lorentz symmetries. In contrast to the
models with extra spacetime dimensions, the Einstein-Finsler type gravity
theories are positively with nontrivial nonlinear connection structure,
nonholonomic constraints and torsion induced by generic off-diagonal
coefficients of metrics, and determined by fundamental QG and/or LV effects.Comment: latex2e, 11pt, 34 pages, the version accepted to Class. Quant. Gra
Two-Connection Renormalization and Nonholonomic Gauge Models of Einstein Gravity
A new framework to perturbative quantum gravity is proposed following the
geometry of nonholonomic distributions on (pseudo) Riemannian manifolds. There
are considered such distributions and adapted connections, also completely
defined by a metric structure, when gravitational models with infinite many
couplings reduce to two--loop renormalizable effective actions. We use a key
result from our partner work arXiv:0902.0911 that the classical Einstein
gravity theory can be reformulated equivalently as a nonholonomic gauge model
in the bundle of affine/de Sitter frames on pseudo-Riemannian spacetime. It is
proven that (for a class of nonholonomic constraints and splitting of the
Levi-Civita connection into a "renormalizable" distinguished connection, on a
base background manifold, and a gauge like distortion tensor, in total space) a
nonholonomic differential renormalization procedure for quantum gravitational
fields can be elaborated. Calculation labor is reduced to one- and two-loop
levels and renormalization group equations for nonholonomic configurations.Comment: latex2e, 40 pages, v4, accepted for Int. J. Geom. Meth. Mod. Phys. 7
(2010
New Classes of Off-Diagonal Cosmological Solutions in Einstein Gravity
In this work, we apply the anholonomic deformation method for constructing
new classes of anisotropic cosmological solutions in Einstein gravity and/or
generalizations with nonholonomic variables. There are analyzed four types of,
in general, inhomogeneous metrics, defined with respect to anholonomic frames
and their main geometric properties. Such spacetimes contain as particular
cases certain conformal and/or frame transforms of the well known
Friedman-Robertson-Walker, Bianchi, Kasner and Godel universes and define a
great variety of cosmological models with generic off-diagonal metrics, local
anisotropy and inhomogeneity. It is shown that certain nonholonomic
gravitational configurations may mimic de Sitter like inflation scenaria and
different anisotropic modifications without satisfying any classical
false-vacuum equation of state. Finally, we speculate on perspectives when such
off-diagonal solutions can be related to dark energy and dark matter problems
in modern cosmology.Comment: latex2e, 11pt, 33 pages with table of content, a variant accepted to
IJT
Clifford-Finsler Algebroids and Nonholonomic Einstein-Dirac Structures
We propose a new framework for constructing geometric and physical models on
nonholonomic manifolds provided both with Clifford -- Lie algebroid symmetry
and nonlinear connection structure. Explicit parametrizations of generic
off-diagonal metrics and linear and nonlinear connections define different
types of Finsler, Lagrange and/or Riemann-Cartan spaces. A generalization to
spinor fields and Dirac operators on nonholonomic manifolds motivates the
theory of Clifford algebroids defined as Clifford bundles, in general, enabled
with nonintegrable distributions defining the nonlinear connection. In this
work, we elaborate the algebroid spinor differential geometry and formulate the
(scalar, Proca, graviton, spinor and gauge) field equations on Lie algebroids.
The paper communicates new developments in geometrical formulation of physical
theories and this approach is grounded on a number of previous examples when
exact solutions with generic off-diagonal metrics and generalized symmetries in
modern gravity define nonholonomic spacetime manifolds with uncompactified
extra dimensions.Comment: The manuscript was substantially modified following recommendations
of JMP referee. The former Chapter 2 and Appendix were elliminated. The
Introduction and Conclusion sections were modifie
Exact accelerating solitons in nonholonomic deformation of the KdV equation with two-fold integrable hierarchy
Recently proposed nonholonomic deformation of the KdV equation is solved
through inverse scattering method by constructing AKNS-type Lax pair. Exact and
explicit N-soliton solutions are found for the basic field and the deforming
function showing an unusual accelerated (decelerated) motion. A two-fold
integrable hierarchy is revealed, one with usual higher order dispersion and
the other with novel higher nonholonomic deformations.Comment: 7 pages, 2 figures, latex. Exact explicit exact N-soliton solutions
(through ISM) for KdV field u and deforming function w are included. Version
to be published in J. Phys.
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