scholarly journals Identification of black hole horizons using scalar curvature invariants

2017 ◽  
Vol 35 (2) ◽  
pp. 025013 ◽  
Author(s):  
Alan Coley ◽  
David McNutt
Keyword(s):  
Black Hole ◽  
Scalar Curvature ◽  
Curvature Invariants

SCALAR AVERAGING IN COSMOLOGY

2010 ◽  
Vol 19 (14) ◽  
pp. 2361-2364
Author(s):  
A. A. COLEY
Keyword(s):  
Scalar Curvature ◽  
Cosmological Evolution ◽  
Considerable Importance ◽  
Correct Interpretation ◽  
Curvature Invariants ◽  
Averaging Problem ◽  
Cosmological Data

The averaging problem in cosmology is of considerable importance for the correct interpretation of cosmological data. In this essay an approach to averaging based on scalar curvature invariants is presented, which gives rise to significant effects on cosmological evolution.

scholarly journals On the quantum improved Schwarzschild black hole

2020 ◽  
Vol 35 (04) ◽  
pp. 2050016
Author(s):  
R. Moti ◽  
A. Shojai
Keyword(s):  
Black Hole ◽  
Vacuum Solution ◽  
General Covariance ◽  
Gravitational Coupling ◽  
Curved Space ◽  
Curvature Invariants ◽  
Symmetric Vacuum ◽  
Non Gaussian ◽  
Exact Renormalization Group ◽  
Tensor Square

Deriving the gravitational effective action directly from exact renormalization group is very complicated, if not impossible. Hence, to study the effects of running gravitational coupling which tends to a non-Gaussian UV fixed point (as it is supposed by the asymptotic safety conjecture), two steps are usually adopted. Cutoff identification and improvement of the gravitational coupling to the running one. As suggested in Ref. 1, a function of all independent curvature invariants seems to be the best choice for cutoff identification of gravitational quantum fluctuations in curved space–time and makes the action improvement, which saves the general covariance of theory, possible. Here, we choose Ricci tensor square for this purpose and then the equation of motion of improved gravitational action and its spherically symmetric vacuum solution are obtained. Indeed, its effect on the massive particles’ trajectory and the black hole thermodynamics is studied.

Gravitational collapse and dark universe with LTB geometry

2016 ◽  
Vol 26 (06) ◽  
pp. 1750045 ◽  
Author(s):  
M. Zaeem-ul-Haq Bhatti ◽  
Z. Yousaf
Keyword(s):  
Black Hole ◽  
Electromagnetic Field ◽  
Time Interval ◽  
Curvature Scalar ◽  
Field Equations ◽  
Dark Sector ◽  
Curvature Invariants ◽  
Text Model ◽  
Polynomial Formula ◽  
Electrically Charged

The objective of this paper is to examine the influence of polynomial [Formula: see text] dark sector cosmic terms on the collapse of electrically charged Lemaître–Tolman–Bondi geometry. We explored a class of solutions for [Formula: see text] field equations in the existence of electromagnetic field and under the constraint of constant curvature scalar. The influence of [Formula: see text] model on the dynamics of collapsing object have been discussed by studying its black hole and cosmological horizons. Also, the effects of these dark sources on the time interval between the corresponding singularities and horizons have been studied. We investigated that the process of collapse slows down due to the higher order curvature invariants of polynomial [Formula: see text] model and electromagnetic field.

An inequality between intrinsic and extrinsic scalar curvature invariants for codimension 2 embeddings

2004 ◽  
Vol 52 (2) ◽  
pp. 101-112 ◽  
Author(s):  
Franki Dillen ◽  
Stefan Haesen ◽  
Miroslava Petrović-Torgašev ◽  
Leopold Verstraelen
Keyword(s):  
Scalar Curvature ◽  
Curvature Invariants

scholarly journals Basis for scalar curvature invariants in three dimensions

2014 ◽  
Vol 31 (23) ◽  
pp. 235010 ◽  
Author(s):  
A A Coley ◽  
A MacDougall ◽  
D D McNutt
Keyword(s):  
Scalar Curvature ◽  
Three Dimensions ◽  
Curvature Invariants

scholarly journals Curvature operators and scalar curvature invariants

2010 ◽  
Vol 27 (9) ◽  
pp. 095014 ◽  
Author(s):  
Sigbjørn Hervik ◽  
Alan Coley
Keyword(s):  
Scalar Curvature ◽  
Curvature Invariants

A note on the circle actions on Einstein manifolds

2001 ◽  
Vol 63 (1) ◽  
pp. 83-91
Author(s):  
Seungsu Hwang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Curvature ◽  
Einstein Manifold ◽  
Orbit Space ◽  
Circle Action ◽  
Fundamental Result ◽  
Einstein Manifolds ◽  
Circle Actions ◽  
Zero Scalar Curvature

A fundamental result in the theory of black holes due to Hawking asserts that the event horizon of a black hole in the stationary space-time is a 2-sphere topologically. In this article we prove the Riemannian analogue of Hawking's result. In other words, we prove that each bolt of a 4-dimensional complete noncompact Einstein manifold of zero scalar curvature admitting a semifree isometric circle action is a 2-sphere topologically. We also study the structure of the orbit space of an Einstein manifold admitting a free isometric circle action.

scholarly journals KILLING VECTORS IN HIGHER-DIMENSIONAL SPACETIMES WITH CONSTANT SCALAR CURVATURE INVARIANTS

2010 ◽  
Vol 07 (08) ◽  
pp. 1349-1369 ◽  
Author(s):  
DAVID MCNUTT ◽  
NICOS PELAVAS ◽  
ALAN COLEY
Keyword(s):  
Scalar Curvature ◽  
Constant Scalar Curvature ◽  
Null Vector ◽  
Killing Vectors ◽  
Curvature Invariants ◽  
Higher Dimensional ◽  
Metric Functions ◽  
Kundt Spacetimes

We study the existence of a non-spacelike isometry, ζ, in higher-dimensional Kundt spacetimes with constant scalar curvature invariants (CSI). We present the particular forms for the null or timelike Killing vectors and a set of constraints for the metric functions in each case. Within the class of N-dimensional CSI Kundt spacetimes, admitting a non-spacelike isometry, we determine which of these can admit a covariantly constant null vector that also satisfy ζ[a;b] = 0.

scholarly journals Curvature invariants and lower dimensional black hole horizons

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Daniele Gregoris ◽  
Yen Chin Ong ◽  
Bin Wang
Keyword(s):  
Black Hole ◽  
Local Extremum ◽  
Tidal Force ◽  
Curvature Invariants ◽  
Dimensional Spacetime ◽  
Dimensional Black Hole ◽  
Cartan Invariants ◽  
Cartan Curvature ◽  
Curvature Tensors ◽  
Lower Dimensional

AbstractIt is known that the event horizon of a black hole can often be identified from the zeroes of some curvature invariants. The situation in lower dimensions has not been thoroughly clarified. In this work we investigate both ($$2+1$$2+1)- and ($$1+1$$1+1)-dimensional black hole horizons of static, stationary and dynamical black holes, identified with the zeroes of scalar polynomial and Cartan curvature invariants, with the purpose of discriminating the different roles played by the Weyl and Riemann curvature tensors. The situations and applicability of the methods are found to be quite different from that in 4-dimensional spacetime. The suitable Cartan invariants employed for detecting the horizon can be interpreted as a local extremum of the tidal force suggesting that the horizon of a black hole is a genuine special hypersurface within the full manifold, contrary to the usual claim that there is nothing special at the horizon, which is said to be a consequence of the equivalence principle.

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