scholarly journals SPHERICALLY SYMMETRIC SPACE–TIME WITH REGULAR DE SITTER CENTER

2003 ◽  
Vol 12 (06) ◽  
pp. 1015-1034 ◽  
Author(s):  
IRINA DYMNIKOVA
Keyword(s):  
Black Hole ◽  
Energy Condition ◽  
Space Time ◽  
Cosmological Term ◽  
Spherically Symmetric ◽  
De Sitter ◽  
Sitter Group ◽  
Class Invariant ◽  
Time Symmetry ◽  
De Sitter Vacuum

We formulate the requirements which lead to the existence of a class of globally regular solutions of the minimally coupled GR equations asymptotically de Sitter at the center. The source term for this class, invariant under boosts in the radial direction, is classified as spherically symmetric vacuum with variable density and pressure [Formula: see text] associated with an r-dependent cosmological term [Formula: see text], whose asymptotic at the origin, dictated by the weak energy condition, is the Einstein cosmological term Λgμν, while asymptotic at infinity is de Sitter vacuum with λ < Λ or Minkowski vacuum. For this class of metrics the mass m defined by the standard ADM formula is related to both the de Sitter vacuum trapped at the origin and the breaking of space–time symmetry. In the case of the flat asymptotic, space–time symmetry changes smoothly from the de Sitter group at the center to the Lorentz group at infinity through radial boosts in between. Geometry is asymptotically de Sitter as r → 0 and asymptotically Schwarzschild at large r. In the range of masses m ≥ m crit , the de Sitter–Schwarzschild geometry describes a vacuum nonsingular black hole (ΛBH), and for m < m crit it describes G-lump — a vacuum selfgravitating particle-like structure without horizons. In the case of de Sitter asymptotic at infinity, geometry is asymptotically de Sitter as r → 0 and asymptotically Schwarzschild–de Sitter at large r. Λμν geometry describes, dependently on parameters m and [Formula: see text] and choice of coordinates, a vacuum nonsingular cosmological black hole, self-gravitating particle-like structure at the de Sitter background λgμν, and regular cosmological models with cosmological constant evolving smoothly from Λ to λ.

Unification of dark energy and dark matter based on the Petrov classification and space-time symmetry

2016 ◽  
Vol 31 (02n03) ◽  
pp. 1641005 ◽  
Author(s):  
Irina Dymnikova
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Space Time ◽  
Cosmological Term ◽  
De Sitter ◽  
Dark Fluid ◽  
Time Symmetry ◽  
Stress Energy ◽  
Petrov Classification ◽  
De Sitter Vacuum

The Petrov classification of stress-energy tensors provides a model-independent definition of a vacuum by the algebraic structure of its stress-energy tensor and implies the existence of vacua whose symmetry is reduced as compared with the maximally symmetric de Sitter vacuum associated with the Einstein cosmological term. This allows to describe a vacuum in general setting by dynamical vacuum dark fluid, presented by a variable cosmological term with the reduced symmetry which makes vacuum dark fluid essentially anisotropic and allows it to be evolving and clustering. The relevant regular solutions to the Einstein equations describe regular cosmological models with time-evolving and spatially inhomogeneous vacuum dark energy, and compact vacuum objects generically related to a dark energy through the de Sitter vacuum interior: regular black holes, their remnants and self-gravitating vacuum solitons — which can be responsible for observational effects typically related to a dark matter. The mass of objects with de Sitter interior is generically related to vacuum dark energy and to breaking of space-time symmetry.

scholarly journals Appearance of a Minimal Length ine+e-Annihilation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Irina Dymnikova ◽  
Alexander Sakharov ◽  
Jürgen Ulbricht
Keyword(s):  
Energy Condition ◽  
Minimal Length ◽  
Nonlinear Electrodynamics ◽  
Perfect Conductor ◽  
De Sitter ◽  
Electromagnetic Mass ◽  
Time Symmetry ◽  
Electromagnetic Soliton ◽  
De Sitter Vacuum ◽  
Arbitrary Gauge

Experimental data reveal with a 5σsignificance the existence of a characteristic minimal lengthle=1.57×10-17 cm at the scaleE=1.253TeV in the annihilation reactione+e-→γγ(γ). Nonlinear electrodynamics coupled to gravity and satisfying the weak energy condition predicts, for an arbitrary gauge invariant Lagrangian, the existence of spinning charged electromagnetic soliton asymptotically Kerr-Newman for a distant observer with the gyromagnetic ratiog=2. Its internal structure includes a rotating equatorial disk of de Sitter vacuum which has properties of a perfect conductor and ideal diamagnetic, displays superconducting behavior, supplies a particle with the finite positive electromagnetic mass related to breaking of space-time symmetry, and gives some idea about the physical origin of a minimal length in annihilation.

scholarly journals Regular rotating electrically charged structures in nonlinear electrodynamics minimally coupled to gravity

2016 ◽  
Vol 41 ◽  
pp. 1660120 ◽  
Author(s):  
Irina Dymnikova ◽  
Evgeny Galaktionov
Keyword(s):  
Energy Condition ◽  
Weak Energy Condition ◽  
Nonlinear Electrodynamics ◽  
Perfect Conductor ◽  
Spherically Symmetric ◽  
Axially Symmetric ◽  
De Sitter ◽  
Superconducting Current ◽  
De Sitter Vacuum ◽  
Electrically Charged

In nonlinear electrodynamics minimally coupled to gravity, regular spherically symmetric electrically charged solutions satisfy the weak energy condition and have obligatory de Sitter center. By the Gürses-Gürsey algorithm they are transformed to regular axially symmetric solutions asymptotically Kerr-Newman for a distant observer. Rotation transforms de Sitter center into de Sitter equatorial disk embedded as a bridge into a de Sitter vacuum surface. The de Sitter surfaces satisfy [Formula: see text] and have properties of a perfect conductor and ideal diamagnetic. The Kerr ring singularity is replaced with the superconducting current which serves as a non-dissipative electromagnetic source of the asymptotically Kerr-Newman geometry. Violation of the weak energy condition is prevented by the basic requirement of electrodynamics of continued media.

A tale of two horizons

2015 ◽  
Vol 93 (9) ◽  
pp. 995-998 ◽  
Author(s):  
Sean Stotyn
Keyword(s):  
Black Hole ◽  
Black Hole Entropy ◽  
Space Time ◽  
Extremal Black Hole ◽  
Spherically Symmetric ◽  
De Sitter ◽  
Event Horizons ◽  
Extremal Limit ◽  
Horizon Geometry ◽  
Killing Horizons

I revisit the fate of coinciding horizons and the volume between them in the extremal limit of spherically symmetric black holes in four space–time dimensions, focusing on the Schwarzschild – de Sitter black hole for concreteness. The two Killing horizons in the limit space–time that are traditionally identified with the limiting event horizons of the non-extremal black hole are shown to instead be generated by an enhanced symmetry of the near horizon geometry (NHG). This dismantles the interpretation of the four-volume between the horizons remaining finite in the extremal limit. The NHG is reinterpreted as a tangent space–time to the degenerate black hole horizon, and geometrical objects, such as Killing vectors and Killing horizons, are carefully mapped between the bulk and the NHG. The implications for extremal black hole entropy are then discussed.

scholarly journals LUKEWARM BLACK HOLES IN QUADRATIC GRAVITY

2011 ◽  
Vol 26 (14) ◽  
pp. 999-1007 ◽  
Author(s):  
JERZY MATYJASEK ◽  
KATARZYNA ZWIERZCHOWSKA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Fourth Order ◽  
Spherically Symmetric ◽  
Cosmological Horizon ◽  
De Sitter ◽  
Quadratic Gravity ◽  
De Sitter Universe ◽  
Electrically Charged

Perturbative solutions to the fourth-order gravity describing spherically-symmetric, static and electrically charged black hole in an asymptotically de Sitter universe is constructed and discussed. Special emphasis is put on the lukewarm configurations, in which the temperature of the event horizon equals the temperature of the cosmological horizon.

scholarly journals The Accurate Modification of Tunneling Radiation of Fermions with Arbitrary Spin in Kerr-de Sitter Black Hole Space-Time

2020 ◽  
Vol 2020 ◽  
pp. 1-6 ◽  
Author(s):  
Bei Sha ◽  
Zhi-E Liu ◽  
Xia Tan ◽  
Yu-Zhen Liu ◽  
Jie Zhang
Keyword(s):  
Black Hole ◽  
Dispersion Relation ◽  
String Theory ◽  
Event Horizon ◽  
Quantum Tunneling ◽  
Gravitational Theory ◽  
Arbitrary Spin ◽  
Space Time ◽  
De Sitter ◽  
Tunneling Radiation

The quantum tunneling radiation of fermions with arbitrary spin at the event horizon of Kerr-de Sitter black hole is accurately modified by using the dispersion relation proposed in the study of string theory and quantum gravitational theory. The derived tunneling rate and temperature at the black hole horizons are analyzed and studied.

scholarly journals On the Energy of a Non-Singular Black Hole Solution Satisfying the Weak Energy Condition

Universe ◽  
2020 ◽  
Vol 6 (10) ◽  
pp. 169
Author(s):  
Irina Radinschi ◽  
Theophanes Grammenos ◽  
Farook Rahaman ◽  
Marius-Mihai Cazacu ◽  
Andromahi Spanou ◽  
...  
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Energy Distribution ◽  
Black Hole Solution ◽  
Energy Condition ◽  
Weak Energy Condition ◽  
Radial Coordinate ◽  
Spherically Symmetric ◽  
Comparison Of The Results ◽  
Two Parameters

The energy-momentum localization for a new four-dimensional and spherically symmetric, charged black hole solution that through a coupling of general relativity with non-linear electrodynamics is everywhere non-singular while it satisfies the weak energy condition, is investigated. The Einstein and Møller energy-momentum complexes have been employed in order to calculate the energy distribution and the momenta for the aforesaid solution. It is found that the energy distribution depends explicitly on the mass and the charge of the black hole, on two parameters arising from the space-time geometry considered, and on the radial coordinate. Further, in both prescriptions all the momenta vanish. In addition, a comparison of the results obtained by the two energy-momentum complexes is made, whereby some limiting and particular cases are pointed out.

scholarly journals Dimensionally Compactified Chern-Simon Theory in 5D as a Gravitation Theory in 4D

2017 ◽  
Vol 45 ◽  
pp. 1760005 ◽  
Author(s):  
Ivan Morales ◽  
Bruno Neves ◽  
Zui Oporto ◽  
Olivier Piguet
Keyword(s):  
Dimensional Space ◽  
Cosmological Solution ◽  
Space Time ◽  
Gravitation Theory ◽  
Simons Theory ◽  
De Sitter ◽  
Field Equations ◽  
Sitter Group ◽  
Dimensional Space Time ◽  
Chern Simons

We propose a gravitation theory in 4 dimensional space-time obtained by compacting to 4 dimensions the five dimensional topological Chern-Simons theory with the gauge group SO(1,5) or SO(2,4) – the de Sitter or anti-de Sitter group of 5-dimensional space-time. In the resulting theory, torsion, which is solution of the field equations as in any gravitation theory in the first order formalism, is not necessarily zero. However, a cosmological solution with zero torsion exists, which reproduces the Lambda-CDM cosmological solution of General Relativity. A realistic solution with spherical symmetry is also obtained.

scholarly journals ENTROPY FROM THE FOAM II

2002 ◽  
Vol 17 (14) ◽  
pp. 1965-1977 ◽  
Author(s):  
REMO GARATTINI
Keyword(s):  
Black Hole ◽  
Simple Model ◽  
Semiclassical Approximation ◽  
Space Time ◽  
The Other ◽  
Charged Black Hole ◽  
De Sitter ◽  
Different Types

A simple model of space–time foam, made by two different types of wormholes in a semiclassical approximation, is taken under examination: one type is a collection of Nw Schwarzschild wormholes, while the other one is made by Schwarzschild–Anti-de Sitter wormholes. The area quantization related to the entropy via the Bekenstein–Hawking formula hints a possible selection between the two configurations. Application to the charged black hole are discussed.

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