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Emil M. Prodanov

Publications and source records attributed to Emil M. Prodanov.

31 records · Page 2Linked to original sources
arXiv2007

Reissner-Nordstrom Expansion

We propose a classical mechanism for the cosmic expansion during the radiation-dominated era. This mechanism assumes that the Universe is a two-component gas. The first component is a gas of ultra-relativistic "normal" particles described by an equation of state of an ideal quantum gas of massless particles. The second component consist of "unusual" charged particles (namely, either with ultra-high charge or with ultra-high mass) that provide the important mechanism of expansion due to their interaction with the "normal" component of the gas. This interaction is described by the Reissner--Nordström metric purely geometrically -- the ``unusual'' particles are modeled as zero-dimensional naked singularities inside spheres of gravitational repulsion. The radius of a repulsive sphere is inversely proportional to the energy of an incoming particle or the temperature. The expansion mechanism is based on the inflating of the "unusual" particles (of charge $Q$) with the drop of the temperature -- this drives apart all neutral particles and particles of specific charge $q/m$ such that ${sign}(Q) q/m \ge - 1$. The Reissner--Nordström expansion naturally ends at recombination. We discuss the range of model parameters within which the proposed expansion mechanism is consistent with the restrictions regarding quantum effects.

hep-th↗
arXiv2005

Haunted Kaluza Universe with Four-dimensional Lorentzian Flat, Kerr, and Taub-NUT Slices

The duality between the original Kaluza's theory and Klein's subsequent modification is duality between slicing and threading decomposition of the five-dimensional spacetime. The field equations of the original Kaluza's theory lead to the interpretation of the four-dimensional Lorentzian Kerr and Taub--NUT solutions as resulting from static electric and magnetic charges and dipoles in the presence of ghost matter and constant dilaton, which models Newton's constant.

hep-th↗
arXiv2005

On the Field Equations of Kaluza's Theory

The field equations of the original Kaluza's theory are analyzed and it is shown that they lead to modification of Einstein's equations. The appearing extra energy-momentum tensor is studied and an example is given where this extra energy-momentum tensor is shown to allow four-dimensional Schwarzschild geometry to accommodate electrostatics. Such deviation from Reissner-Nordstrom geometry can account for the interpretation of Schwarzschild geometry as resulting not from mass only, but from the combined effects of mass and electric charge, even electric charge alone.

hep-th↗
arXiv2005

Pseudo-Newtonian Potential for Charged Particle in Kerr-Newman Geometry

We consider the equatorial circular motion of a test particle of specific charge q/m << 1 in the Kerr-Newman geometry of a rotating charged black hole. We find the particle's conserved energy and conserved projection of the angular momentum on the black hole's axis of rotation as corrections, in leading order of q/m, to the corresponding energy and angular momentum of a neutral particle. We determine the centripetal force acting on the test particle and, consequently, we find a classical pseudo-Newtonian potential with which one can mimic this general relativistic problem.

gr-qc↗
arXiv2004

Riemann Tensor of the Ambient Universe, the Dilaton and the Newton's Constant

We investigate a four-dimensional world, embedded into a five-dimensional spacetime, and find the five-dimensional Riemann tensor via generalisation of the Gauss (--Codacci) equations. We then derive the generalised equations of the four-dimensional world and also show that the square of the dilaton field is equal to the Newton's constant. We find plausable constant and non-constant solutions for the dilaton.

hep-th↗
arXiv2001

Bouncing Branes

Two classical scalar fields are minimally coupled to gravity in the Kachru-Shulz-Silverstein scenario with a rolling fifth radius. A Tolman wormhole solution is found for a R x S^3 brane with Lorentz metric and for a R x AdS_3 brane with positive definite metric.

hep-th↗
arXiv2001

Standard Cosmology on a Self-Tuning Domain Wall

We investigate the cosmology of (4+1)-dimensional gravity coupled to a scalar field and a bulk anisotropic fluid within the context of the single-brane Randall-Sundrum scenario. Assuming a separable metric, a static fifth radius and the scalar to depend only on the fifth direction, we find that the warp factor is given as in the papers of Kachru, Schulz and Silverstein [hep-th/0001206, hep-th/0002121] and that the cosmology on a self-tuning brane is standard. In particular, for a radiation-dominated brane the pressure in the fifth direction vanishes.

hep-th↗
arXiv2000

A remark on Schwarz's topological field theory

The standard evaluation of the partition function $Z$ of Schwarz's topological field theory results in the Ray--Singer analytic torsion. Here we present an alternative evaluation which results in Z=1. Mathematically, this amounts to a novel perspective on analytic torsion: it can be formally written as a ratio of volumes of spaces of differential forms which is formally equal to 1 by Hodge duality. An analogous result for Reidemeister combinatorial torsion is also obtained.

hep-th↗
arXiv2000

Standard Cosmology from Sigma-Model

We investigate (4+1)- and (5+0)-dimensional gravity coupled to a non-compact scalar field sigma-model and a perfect fluid within the context of the Randall-Sundrum scenario. We find cosmological solutions with a rolling fifth radius and a family of warp factors. Included in this family are both the original Randall-Sundrum solution and the self-tuning solution of Kachru, Schulz and Silverstein. Our solutions exhibit conventional cosmology.

hep-th↗
arXiv1999

Abelian Duality

We show that on three-dimensional Riemannian manifolds without boundaries and with trivial first real de Rham cohomology group (and in no other dimensions) scalar field theory and Maxwell theory are equivalent: the ratio of the partition functions is given by the Ray-Singer torsion of the manifold. On the level of interaction with external currents, the equivalence persists provided there is a fixed relation between the charges and the currents.

hep-th↗
arXiv1998

On the Absence of Cross-Confinement for Dynamically Generated Multi-Chern-Simons Theories

We show that when the induced parity breaking part of the effective action for the low-momentum region of U(1) x ... x U(1) Maxwell gauge field theory with massive fermions in 3 dimensions is coupled to a ϕ^4 scalar field theory, it is not possible to eliminate the screening of the long-range Coulomb interactions and get external charges confined in the broken Higgs phase. This result is valid for non-zero temperature as well.

hep-th↗