Related papers: Kerr-de Sitter spacetime, Penrose process and the …
It is shown that the Kerr black hole could act as accelerators for spinning particles. In principle, it could obtain arbitrarily high energy for extremal Kerr black hole. In this paper, we extend the previous research to the Kerr-(anti-)de…
We study quantum mechanical and classical stability properties of Reissner-Nordstrom deSitter spacetimes, which describe black holes with mass $M$ and charge $Q$ in a background with cosmological constant $\Lambda \ge 0$. There are two…
The Newman-Penrose formalism is used to derive the Teukolsky master equations controlling massless scalar, neutrino, electromagnetic, gravitino, and gravitational field perturbations of the Kerr-de Sitter spacetime. Then the quantum entropy…
This paper examines regular black holes, in particular the Bardeen spacetime where singularities are replaced by non-singular cores. It explores the energy extraction through the charged Penrose process and shows that magnetic charge…
A new solution of the Einstein equations for the point mass immersed in the de Sitter Universe is presented. The properties of the metric are very different from both the Schwarzschild black hole and the de Sitter Universe: it is everywhere…
A new scenario for extracting energy from a Kerr black hole is proposed. With magnetic field lines connecting plasma particles inside the ergosphere with remote loads, the frame dragging twists the field lines so that energy and angular…
With the basic cosmological relations that agree with the recent observations, simple expressions are suggested concerning the value of cosmological constant($\Lambda$). A large contribution of quantum vacuum to the energy momentum tensor…
We examine potential deformations of inner black hole and cosmological horizons in Reissner-Nordstr\"om de-Sitter spacetimes. While the rigidity of the outer black hole horizon is guaranteed by theorem, that theorem applies to neither the…
Taking the mass, charge, hair parameter, and cosmological constant of the 5-dimensional de Sitter hairy spacetime as the state variables of a thermodynamic system, and based on the satisfaction of the universal first law of thermodynamics,…
In this study, the methodology proposed by Goon and Penco for investigating the universality on thermodynamic relations with corrections in de Sitter black holes is extended. A universal thermodynamic extremality relation, under…
Recent work indicates that the strong cosmic censorship hypothesis is violated by nearly extremal Reissner-Nordstrom-de Sitter black holes. It was argued that perturbations of such a black hole decay sufficiently rapidly that the perturbed…
In this research work, predominantly we acquire area, angular velocity, entropy, surface gravity and Hawking temperature of inner and outer horizons for Kerr-Newman black hole in presence of quintessence. Additionally, we determine area…
The equations of general relativity in the form of timelike and null geodesics that describe motion of test particles and photons in Kerr spacetime are solved exactly including the contribution from the cosmological constant. We then…
Interpreting the cosmological constant as the energy of the vacuum and using a gravitational decoupling approach leads to a new Kerr--anti-de Sitter (AdS) black hole. The metric of the new Kerr--AdS is simpler than the standard Kerr--AdS…
We calculate the total gravitational energy and the gravitational energy density of the de Sitter space using the definition of localized energy that arises in the framework of the teleparallel equivalent of general relativity. We find that…
We show that in any model of non-eternal inflation satisfying the null energy condition, the area of the de Sitter horizon increases by at least one Planck unit in each inflationary e-folding. This observation gives an operational meaning…
Earlier it was shown that the entropy of an ideal gas, contained in a box and moving in a gravitational field, develops an area dependence when it approaches the horizon of a static, spherically symmetric spacetime. Here we extend the above…
According to the Cosmic Censorship Conjecture, all the singularities produced by the collapsing matter must be hidden behind an event horizon. In 4D general relativity, this implies that the final product of the collapse is a Kerr-Newman…
Penrose's Strong Cosmic Censorship conjecture safeguards determinism in General Relativity. Within the initial value approach to General Relativity, proof of Strong Cosmic Censorship preservation is predicated on the unique evolution of the…
We analyze in detail the geometry and dynamics of the cosmological region arising in spherically symmetric black hole solutions of the Einstein-Maxwell-scalar field system with a positive cosmological constant. More precisely, we solve, for…