[Show abstract][Hide abstract] ABSTRACT: In non-linear electrodynamics coupled to gravity, regular spherically symmetric electrically charged solutions satisfy the weak energy condition and have an obligatory de Sitter center. By the Gürses-Gürsey algorithm they are transformed to spinning electrically charged solutions that are asymptotically Kerr-Newman for a distant observer. Rotation transforms the de Sitter center into a de Sitter vacuum surface which contains the equatorial disk r = 0 as a bridge. We present a general analysis of the horizons, ergoregions and de Sitter surfaces, as well as the conditions of the existence of regular solutions to the field equations. We find asymptotic solutions and show that de Sitter vacuum surfaces have properties of a perfect conductor and ideal diamagnetic, violation of the weak energy condition is prevented by the basic requirement of electrodynamics of continued media, and the Kerr ring singularity is replaced with the superconducting current.
[Show abstract][Hide abstract] ABSTRACT: We address the question of correct description of Lagrange dynamics for regular electrically charged structures in nonlinear electrodynamics coupled to gravity. Regular spherically symmetric configuration satisfying the weak energy condition has obligatory de Sitter center in which the electric field vanishes while the energy density of electromagnetic vacuum achieves its maximal value. The Maxwell weak field limit as requires vanishing electric field at infinity. A field invariant evolves between two minus zero in the center and at infinity which makes a Lagrangian with nonequal asymptotic limits inevitably branching. We formulate the appropriate nonuniform variational problem including the proper boundary conditions and present the example of the spherically symmetric Lagrangian describing electrically charged structure with the regular center.
[Show abstract][Hide abstract] ABSTRACT: We present a family of spherically symmetric multihorizon spacetimes with a vacuum dark fluid, associated with a time-dependent and spatially inhomogeneous cosmological term. The vacuum dark fluid is defined in a model-independent way by the symmetry of its stress–energy tensor, i.e. its invariance under Lorentz boosts in a distinguished spatial direction (pr = −ρ for the spherically symmetric fluid), which makes dark fluid essentially anisotropic and allows its density to evolve. The related cosmological models belong to the Lemaître class of models with anisotropic fluids and describe evolution of a universe with several scales of vacuum energy related to phase transitions during its evolution. The typical behavior of solutions and the number of spacetime horizons are determined by the number of vacuum scales. We study in detail the model with three vacuum scales: GUT, QCD and that responsible for the present accelerated expansion. The model parameters are fixed by the observational data and by conditions of analyticity and causality. We find that our Universe has three horizons. During the first inflation, the Universe enters a T-region, which makes expansion irreversible. After second phase transition at the QCD scale, the Universe enters R-region, where for a long time its geometry remains almost pseudo-Euclidean. After crossing the third horizon related to the present vacuum density, the Universe should have to enter the next T-region with the inevitable expansion.
[Show abstract][Hide abstract] ABSTRACT: We outline the properties and possible observational signatures of gravitational vacuum solitons (G-lumps) which are spherically
symmetric, globally neutral, gravitationally bound compact vacuum objects without horizons, asymptotically de Sitter at the
center. Their existence is implied by the Einstein equations. Their masses are restricted by m < m
crit, where m
crit = αmp1 √ϱ0/ϱp1 with a coefficient α depending on the model. G-lumps can be considered as dark matter candidates which are generically related to vacuum dark
energy through the de Sitter vacuum trapped inside.
Gravitation and Cosmology 01/2011; 17(1):38-41. DOI:10.1134/S0202289311010087 · 0.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A unified description of dark ingredients is realized by a vacuum dark fluid defined by symmetry of its stress-energy tensor
and allowed by General Relativity. The symmetry is reduced compared with the maximally symmetric de Sitter vacuum, which makes
vacuum dark fluid essentially anisotropic and allows its density and pressure to evolve. It represents distributed vacuum
dark energy by a time-evolving and spatially inhomogeneous cosmological term, and vacuum dark matter by gravitational vacuum
solitons which are regular gravitationally bound structures without horizons (dark particles or dark stars), with the de Sitter
centre (Λδ
k
i
) in de Sitter space (λδ
k
i
).
Keywordsvacuum dark energy–dark matter
Central European Journal of Physics 06/2010; 9(3):644-653. DOI:10.2478/s11534-010-0071-3 · 1.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We address the question of unified description of dark ingredients in the Universe by a vacuum dark fluid with continuous density and pressures, which represents both distributed vacuum dark energy by a time evolving and spatially inhomogeneous cosmological term, and compact self-gravitating objects with de Sitter vacuum trapped inside. The existence of spherically symmetric globally neutral gravitationally bound vacuum objects without horizons (called G-lumps) asymptotically de Sitter at the center, is implied by the Einstein equations. Their masses are restricted by m<mcrit where with a coefficient α depending on the model. We introduce vacuum dark fluid and present the criterion of stability of G-lumps to external polar perturbations.
Physics Letters B 02/2007; 645(4-645):358-364. DOI:10.1016/j.physletb.2006.12.047 · 6.13 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This is the first of series of papers in which we investigate stability of the spherically symmetric spacetime with de Sitter centre. Geometry, asymptotically Schwarzschild for large r and asymptotically de Sitter as r → 0, describes a vacuum non-singular black hole for m ≥ mcr and particle-like self-gravitating structure for m < mcr where a critical value mcr depends on the scale of the symmetry restoration to the de Sitter group in the origin. In this paper, we address the question of stability of a vacuum non-singular black hole with de Sitter centre to external perturbations. We specify first two types of geometries with and without changes of topology. Then we derive the general equations governing polar perturbations, specify criteria of stability for a regular black hole with de Sitter centre, and study in detail the case of the density profile where ρ0 is the density of de Sitter vacuum at the centre, is the de Sitter radius and rg is the Schwarzschild radius.