scholarly journals NULL GEODESICS IN BRANE WORLD UNIVERSE

2001 ◽  
Vol 16 (37) ◽  
pp. 2371-2380 ◽  
Author(s):  
DONAM YOUM
Keyword(s):  
Black Hole ◽  
Gravitational Force ◽  
Null Geodesic ◽  
Brane World ◽  
Lower Dimension ◽  
Geodesic Motion ◽  
Null Geodesics ◽  
Static Universe ◽  
Additional Influence

We study null bulk geodesic motion in the brane world cosmology in the RS2 scenario and in the static universe in the bulk of the charged topological AdS black hole. We obtain equations describing the null bulk geodesic motion as observed in one lower dimension. We find that the null geodesic motion in the bulk of the brane world cosmology in the RS2 scenario is observed to be under the additional influence of extra non-gravitational force by the observer on the three-brane, if the brane universe does not possess the Z2 symmetry. As for the null geodesic motion in the static universe in the bulk of the charged AdS black hole, the extra force is realized even when the brane universe has the Z2 symmetry.

scholarly journals Null geodesics and repulsive behavior of gravity in $(2+1)$D massive gravity

2019 ◽  
Vol 2019 (7) ◽  
Author(s):  
Keisuke Nakashi ◽  
Shinpei Kobayashi ◽  
Shu Ueda ◽  
Hiromi Saida
Keyword(s):  
Black Hole ◽  
Deflection Angle ◽  
Null Geodesic ◽  
Analytic Solutions ◽  
Massive Gravity ◽  
Geodesic Equation ◽  
Null Geodesics ◽  
Black Hole Background ◽  
Black Hole Spacetime ◽  
The Impact

Abstract We study the null geodesics in a static circularly symmetric (SCS) black hole spacetime, which is a solution in the $(2+1)$D massive gravity proposed by Bergshoeff, Hohm, and Townsend (BHT massive gravity). We obtain analytic solutions for the null geodesic equation in the SCS black hole background and find the explicit form of deflection angles. We see that, for various values of the impact parameter, the deflection angle can be positive, negative, or even zero in this black hole spacetime. The negative deflection angle indicates the repulsive behavior of the gravity that comes from the gravitational hair parameter that is the most characteristic quantity of the BHT massive gravity.

scholarly journals Behavior of null-geodesics in the interior of Reissner–Nordstrom black hole

2019 ◽  
Vol 31 (07) ◽  
pp. 1950021
Author(s):  
G. Eskin
Keyword(s):  
Black Hole ◽  
Null Geodesic ◽  
Geometric Optics ◽  
Null Geodesics ◽  
Outer Horizon ◽  
Inner Horizon ◽  
Plane Passing

We show that an incoming null-geodesic belonging to a plane passing through the origin and starting outside the outer horizon crosses the outer and the inner horizons. Then it turns at some point inside the inner horizon and approaches the inner horizon when the time tends to infinity. We also construct a geometric optics solution of the Reissner–Nordstrom equation that has support in a neighborhood of the null-geodesic.

scholarly journals Null geodesics and thermodynamic phase transition of four-dimensional Gauss–Bonnet AdS black hole

2021 ◽  
pp. 168461
Author(s):  
Kartheek Hegde ◽  
Naveena Kumara A. ◽  
Ahmed Rizwan C.L. ◽  
Md Sabir Ali ◽  
Ajith K.M.
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Null Geodesics ◽  
Thermodynamic Phase

scholarly journals Null Geodesics and Strong Field Gravitational Lensing in a String Cloud Background

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
M. Sharif ◽  
Sehrish Iftikhar
Keyword(s):  
Black Hole ◽  
Gravitational Lensing ◽  
Galactic Center ◽  
Deflection Angle ◽  
Orbital Motion ◽  
Strong Field ◽  
Schwarzschild Black Hole ◽  
Field Limit ◽  
Null Geodesics ◽  
Supermassive Black Hole

This paper is devoted to studying two interesting issues of a black hole with string cloud background. Firstly, we investigate null geodesics and find unstable orbital motion of particles. Secondly, we calculate deflection angle in strong field limit. We then find positions, magnifications, and observables of relativistic images for supermassive black hole at the galactic center. We conclude that string parameter highly affects the lensing process and results turn out to be quite different from the Schwarzschild black hole.

scholarly journals Geodesic motion of neutral particles around a Kerr–Newman black hole

2017 ◽  
Vol 34 (23) ◽  
pp. 235008 ◽  
Author(s):  
Chen-Yu Liu ◽  
Da-Shin Lee ◽  
Chi-Yong Lin
Keyword(s):  
Black Hole ◽  
Geodesic Motion ◽  
Neutral Particles ◽  
Newman Black Hole

scholarly journals Lyapunov exponent, ISCO and Kolmogorov–Senai entropy for Kerr–Kiselev black hole

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Monimala Mondal ◽  
Farook Rahaman ◽  
Ksh. Newton Singh
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Lyapunov Exponent ◽  
Circular Orbit ◽  
Real Root ◽  
Angular Frequency ◽  
Geodesic Motion ◽  
Radial Equation ◽  
Stable Circular Orbit ◽  
Innermost Stable Circular Orbit

AbstractGeodesic motion has significant characteristics of space-time. We calculate the principle Lyapunov exponent (LE), which is the inverse of the instability timescale associated with this geodesics and Kolmogorov–Senai (KS) entropy for our rotating Kerr–Kiselev (KK) black hole. We have investigate the existence of stable/unstable equatorial circular orbits via LE and KS entropy for time-like and null circular geodesics. We have shown that both LE and KS entropy can be written in terms of the radial equation of innermost stable circular orbit (ISCO) for time-like circular orbit. Also, we computed the equation marginally bound circular orbit, which gives the radius (smallest real root) of marginally bound circular orbit (MBCO). We found that the null circular geodesics has larger angular frequency than time-like circular geodesics ($$Q_o > Q_{\sigma }$$ Q o > Q σ ). Thus, null-circular geodesics provides the fastest way to circulate KK black holes. Further, it is also to be noted that null circular geodesics has shortest orbital period $$(T_{photon}< T_{ISCO})$$ ( T photon < T ISCO ) among the all possible circular geodesics. Even null circular geodesics traverses fastest than any stable time-like circular geodesics other than the ISCO.

scholarly journals Brane-world generalizations of the Einstein static universe

2002 ◽  
Vol 19 (2) ◽  
pp. 213-221 ◽  
Author(s):  
László Á Gergely ◽  
Roy Maartens
Keyword(s):  
Brane World ◽  
Static Universe ◽  
Einstein Static Universe

Tunneling in Horava–Lifshitz black hole

2013 ◽  
Vol 91 (1) ◽  
pp. 64-70 ◽  
Author(s):  
J. Sadeghi ◽  
A. Banijamali ◽  
E. Reisi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dimensional Space ◽  
Null Geodesic ◽  
Hawking Temperature ◽  
Jacobi Method ◽  
Back Reaction ◽  
Dimensional Space Time ◽  
Lifshitz Black Holes ◽  
Lifshitz Black Hole

In this paper, using the Hamilton–Jacobi method we first calculate the Hawking temperature for a Horava–Lifshitz black hole. Then by utilizing the radial null geodesic method we obtain the entropy of such a black hole in four-dimensional space–time. We also consider the effect of back reaction on the surface gravity and compute modifications of entropy and Hawking temperature because of such an effect. Our calculations are for two kinds of Horava–Lifshitz black holes: Kehagias–Sfetsos and Lu–Mei–Pope.

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