480 citations · 6k across the 156 of their papers we have counts for
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Dyonic Simpson Visser black-bounce spacetime surrounded by an exotic Einstein cluster in general relativity
Pedro Cañate, Joseph Sultana, Demosthenes Kazanas
In this work, we present the Simpson-Visser black-bounce (SV-BB) spacetime with both electric and magnetic charges (the dyonic SV-BB) as an exact solution of general relativity cou…
Gravitational Waves from the Pulsar Magnetosphere
Ioannis Contopoulos, Demosthenes Kazanas, Demetrios B. Papadopoulos
We investigate the generation of gravitational waves from the rotation of an orthogonal pulsar magnetosphere in flat space time. We calculate the first order metric perturbation du…
Gravity Beyond Einstein? Yes, but in Which Direction?
Demosthenes Kazanas, Demetrios Papadopoulos, Dimitris Christodoulou
We present qualitative arguments in favor of an extension of the theory of the gravitational interaction beyond that resulting from the Hilbert-Einstein action. To this end we cons…
Stabilizing Spherical Energy Shells with Angular Momentum in Gravitational Backgrounds
I. Antoniou, D. Kazanas, D. Papadopoulos +1
Spherical energy shells in General Relativity tend to collapse due to gravitational effects and/or due to tension effects. Shell stabilization may be achieved by modifying the grav…
Gravitational analog of the canonical acoustic black hole in Einstein-scalar-Gauss-Bonnet theory
Pedro Cañate, Joseph Sultana, Demosthenes Kazanas
In this work, in the context of modified gravity, a curved spacetime analogous to the "canonical acoustic black hole" is constructed. The source is a self-interacting scalar field…
Conformal Weyl gravity and perihelion precession
Joseph Sultana, Demosthenes Kazanas, Jackson Levi Said
We investigate the perihelion shift of planetary motion in conformal Weyl gravity using the metric of the static, spherically symmetric solution discovered by Mannheim \& Kazanas (…
Ellis wormhole without a phantom scalar field
Pedro Cañate, Joseph Sultana, Demosthenes Kazanas
In this paper, we present an exact solution for -dimensional Einstein-scalar-Gauss-Bonnet theory (EsGB) in electrovacuum. The solution is characterized by only one parameter…
Universal expansion with spatially varying
Dimitris M. Christodoulou, Demosthenes Kazanas
We calculate the expansion of the universe under the assumptions that varies in space and the radial size of the universe is very large (we call this the MOND regime of var…
A no-hair theorem for spherically symmetric black holes in gravity
Joseph Sultana, Demosthenes Kazanas
In a recent paper Cañate (CQG, {\bf 35}, 025018 (2018)) proved a no hair theorem to static and spherically symmetric or stationary axisymmetric black holes in general gravit…
Interposing a Varying Gravitational Constant Between Modified Newtonian Dynamics and Weak Weyl Gravity
Dimitris M. Christodoulou, Demosthenes Kazanas
The Newtonian gravitational constant obeys the dimensional relation , where , , and denote mass, acceleration, and speed, respectively. Since the…
Gauge Choice in Conformal Gravity
Joseph Sultana, Demosthenes Kazanas
In a recent paper (MNRAS 458, 4122 (2016)) K. Horne examined the effect of a conformally coupled scalar field (referred to as Higgs field) on the Mannheim-Kazanas metric ,…
Can gravitational collapse sustain singularity-free trapped surfaces?
Manasse R. Mbonye, Demosthenes Kazanas
In singularity generating spacetimes both the out-going and in-going expansions of null geodesic congruences and should become increasingly negative without bound,…
A non-singular black hole model as a possible end-product of gravitational collapse
Manasse R. Mbonye, Demosthenes Kazanas
In this paper we present a non-singular black hole model as a possible end-product of gravitational collapse. The depicted spacetime which is type [II,(II)], by Petrov classificati…
Higgs Mechanism and the Structure of the Energy-Momentum Tensor in Einstein Gravity and Conformal Gravity
Philip D. Mannheim, Demosthenes Kazanas
In the standard treatment of the Einstein gravitational theory the energy-momentum tensor has always been taken to be composed of perfect fluid aggregates of kinematic Newtonian po…