233 research outputs found
Foam-like structure of the Universe
On the quantum stage spacetime had the foam-like structure. When the Universe
cools, the foam structure tempers and does not disappear. We show that effects
caused by the foamed structure mimic very well the observed Dark Matter
phenomena. Moreover, we show that in a foamed space photons undergo a chaotic
scattering and together with every discrete source of radiation we should
observe a diffuse halo. We show that the distribution of the diffuse halo of
radiation around a point-like source repeats exactly the distribution of dark
matter around the same source, i.e. the DM halos are sources of the diffuse
radiation
Geometric approach to discrete series of unirreps for Vir.
AbstractWe want to realize the discrete series of unirreps for the Virasoro-Bott group Vir (= the central extension of Diff+(S1)) in the space of holomorphic functions on the infinite dimensional Kähler manifold M = Diff+(S1)/S1. The explicit formulae are given for the action of Vir in the space of polynomial functions in the natural complex coordinates on M
On Scattering of Electromagnetic Waves by a Wormhole
We consider scattering of a plane electromagnetic wave by a wormhole. It is
found that the scattered wave is partially depolarized and has a specific
interference picture depending on parameters of the wormhole and the distance
to the observer. It is proposed that such features can be important in the
direct search of wormholes
Quasi-Isotropization of the Inhomogeneous Mixmaster Universe Induced by an Inflationary Process
We derive a ``generic'' inhomogeneous ``bridge'' solution for a cosmological
model in the presence of a real self-interacting scalar field. This solution
connects a Kasner-like regime to an inflationary stage of evolution and
therefore provides a dynamical mechanism for the quasi-isotropization of the
universe. In the framework of a standard Arnowitt-Deser-Misner Hamiltonian
formulation of the dynamics and by adopting Misner-Chitr\`e-like variables, we
integrate the Einstein-Hamilton-Jacobi equation corresponding to a ``generic''
inhomogeneous cosmological model whose evolution is influenced by the coupling
with a bosonic field, expected to be responsible for a spontaneous symmetry
breaking configuration. The dependence of the detailed evolution of the
universe on the initial conditions is then appropriately characterized.Comment: 17 pages, no figure, to appear on PR
Billiard Representation for Multidimensional Quantum Cosmology near the Singularity
The degenerate Lagrangian system describing a lot of cosmological models is
considered. When certain restrictions on the parameters of the model are
imposed, the dynamics of the model near the "singularity" is reduced to a
billiard on the Lobachevsky space. The Wheeler-DeWitt equation in the
asymptotical regime is solved and a third-quantized model is suggested.Comment: 6 pages, LaTe
Dark matter, dark charge, and the fractal structure of the Universe
It is shown that the observed fractal distribution of galaxies is, in fact,
consistent with homogeneity of the Universe and observational limits on , if the presence of dark matter and dark charge predicted by the
Modified Field Theory (MOFT) is taken into account. It is also shown that
indeed in MOFT the ground state for baryons does correspond to the fractal
distribution of baryons with dimension D=2. It is discussed a new scenario of
structure formation in which observed structures appear as a result of decay of
the primordial fractal distribution of baryons.Comment: 4 pages, a short comment to astro-ph/0202302, Latex, replaced with
published version Journal - ref: Phys. Lett. B 535 (2002) pp. 22-2
Dark Matter from a gas of wormholes
The simplistic model of the classical spacetime foam is considered, which
consists of static wormholes embedded in Minkowski spacetime. We explicitly
demonstrate that such a foam structure leads to a topological bias of
point-like sources which can equally be interpreted as the presence of a dark
halo around any point source. It is shown that a non-trivial halo appears on
scales where the topological structure possesses a local inhomogeneity, while
the homogeneous structure reduces to a constant renormalization of the
intensity of sources. We also show that in general dark halos possess both
(positive and negative) signs depending on scales and specific properties of
topological structure of space.Comment: minor corrections (eq. 18
Discrete Dynamics: Gauge Invariance and Quantization
Gauge invariance in discrete dynamical systems and its connection with
quantization are considered. For a complete description of gauge symmetries of
a system we construct explicitly a class of groups unifying in a natural way
the space and internal symmetries. We describe the main features of the gauge
principle relevant to the discrete and finite background. Assuming that
continuous phenomena are approximations of more fundamental discrete processes,
we discuss -- with the help of a simple illustration -- relations between such
processes and their continuous approximations. We propose an approach to
introduce quantum structures in discrete systems, based on finite gauge groups.
In this approach quantization can be interpreted as introduction of gauge
connection of a special kind. We illustrate our approach to quantization by a
simple model and suggest generalization of this model. One of the main tools
for our study is a program written in C.Comment: 15 pages; CASC 2009, Kobe, Japan, September 13-17, 200
Propagation of cosmic rays in the foam-like Universe
The model of a classical spacetime foam is considered, which consists of
static wormholes embedded in Minkowski spacetime. We examine the propagation of
particles in such a medium and demonstrate that a single thin ray undergoes a
specific damping in the density of particles depending on the traversed path
and the distribution of wormholes. The missing particles are scattered around
the ray. Wormholes was shown to form DM halos around point-like sources.
Therefore, the correlation predicted between the damping and the amount of DM
can be used to verify the topological nature of Dark Matter
Symplectic structures associated to Lie-Poisson groups
The Lie-Poisson analogues of the cotangent bundle and coadjoint orbits of a
Lie group are considered. For the natural Poisson brackets the symplectic
leaves in these manifolds are classified and the corresponding symplectic forms
are described. Thus the construction of the Kirillov symplectic form is
generalized for Lie-Poisson groups.Comment: 30 page
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