scholarly journals Conformally symmetric vacuum solutions of the gravitational field equations in the brane-world models

2005 ◽  
Vol 319 (2) ◽  
pp. 471-492 ◽  
Author(s):  
T. Harko ◽  
M.K. Mak
Keyword(s):  
Gravitational Field ◽  
Brane World ◽  
Field Equations ◽  
Gravitational Field Equations ◽  
Symmetric Vacuum ◽  
Vacuum Solutions

scholarly journals Exact Solutions in Poincaré Gauge Gravity Theory

Universe ◽  
2019 ◽  
Vol 5 (5) ◽  
pp. 127 ◽  
Author(s):  
Yuri N. Obukhov
Keyword(s):  
Gravitational Field ◽  
Gravity Models ◽  
Field Potentials ◽  
De Sitter ◽  
Field Equations ◽  
Yang Mills ◽  
Gravitational Field Equations ◽  
Poincaré Symmetry ◽  
Gauge Gravity ◽  
Vacuum Solutions

In the framework of the gauge theory based on the Poincaré symmetry group, the gravitational field is described in terms of the coframe and the local Lorentz connection. Considered as gauge field potentials, they give rise to the corresponding field strength which are naturally identified with the torsion and the curvature on the Riemann–Cartan spacetime. We study the class of quadratic Poincaré gauge gravity models with the most general Yang–Mills type Lagrangian which contains all possible parity-even and parity-odd invariants built from the torsion and the curvature. Exact vacuum solutions of the gravitational field equations are constructed as a certain deformation of de Sitter geometry. They are black holes with nontrivial torsion.

PHYSICAL PROPERTIES OF THE THIN ACCRETION DISK OF THE TAUB-NUT BLACK HOLE

2021 ◽  
Vol 0 (1) ◽  
pp. 87-91
Author(s):  
R.M. YUSUPOVA ◽  
◽  
R.N. ZMAILOV ◽  
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Gravitational Field ◽  
Physical Properties ◽  
Accretion Disk ◽  
Energy Flow ◽  
Field Equations ◽  
Effective Potential Energy ◽  
Gravitational Field Equations ◽  
Vacuum Solutions

The Taub-NUT space-time metric is one of the vacuum solutions to Einstein's gravitational field equations. In this metric, the Newman-Unti-Tamburino parameter (NUT) and its effect on the physical properties of a thin accretion disk are of particular interest. In this paper, calculations are performed to determine the physical properties of a thin accretion disk around the Taub-NUT black hole based on the Page-Thorne model. The influence of the NUT parameter on the angular velocity, binding energy, angular momentum of particles, effective potential, energy flow, and temperature of the accretion disk is revealed. According to the data obtained, the temperature of the accretion disk of the Taub-NUT black hole decreases as the value of the NUT parameter increases.

Can quantum black holes be (q, p)-fermions?

2017 ◽  
Vol 32 (15) ◽  
pp. 1750080 ◽  
Author(s):  
Emre Dil
Keyword(s):  
Black Holes ◽  
Gravitational Field ◽  
Fermi Gas ◽  
Einstein Equations ◽  
Quantum Corrections ◽  
Field Equations ◽  
Gravitational Field Equations ◽  
Entropic Gravity ◽  
Two Parameter

In this study, to investigate the very nature of quantum black holes, we try to relate three independent studies: (q, p)-deformed Fermi gas model, Verlinde’s entropic gravity proposal and Strominger’s quantum black holes obeying the deformed statistics. After summarizing Strominger’s extremal quantum black holes, we represent the thermostatistics of (q, p)-fermions to reach the deformed entropy of the (q, p)-deformed Fermi gas model. Since Strominger’s proposal claims that the quantum black holes obey deformed statistics, this motivates us to describe the statistics of quantum black holes with the (q, p)-deformed fermions. We then apply the Verlinde’s entropic gravity proposal to the entropy of the (q, p)-deformed Fermi gas model which gives the two-parameter deformed Einstein equations describing the gravitational field equations of the extremal quantum black holes obeying the deformed statistics. We finally relate the obtained results with the recent study on other modification of Einstein equations obtained from entropic quantum corrections in the literature.

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