Related papers: Dispersion relation and surface gravity of univers…
To derive black hole thermodynamics in any quantum theory of gravity, one must introduce constraints that ensure that a black hole is actually present. For a large class of black holes, the imposition of such ``horizon constraints'' allows…
Entanglement entropy in local quantum field theories is typically ultraviolet divergent due to short distance effects in the neighbourhood of the entangling region. In the context of gauge/gravity duality, we show that surface terms in…
The presence of gravity implies corrections to the Einstein-Planck formula $E=h \nu$. This gives hope that the divergent blueshift in frequency, associated to the presence of a black hole horizon, could be smoothed out for the energy. Using…
We introduce a calculation, based on purely topological reasoning, of the global equilibrium Hawking temperature of the Schwarzschild-de Sitter spacetime, where a Schwarzschild black hole horizon coexists with a de Sitter cosmological…
Einstein-aether theory is extended by allowing for spinning degrees of freedom of the aether. In addition to the acceleration, shear, expansion, and vorticity of the aether velocity field, a spin rotation describing the dynamics of a…
We develop a new method for calculation of quasi-normal modes of black holes, when the effective potential, which governs black hole perturbations, is known only numerically in some region near the black hole. This method can be applied to…
Evolution of gravitational perturbations, both in time and frequency domains, is considered for a spherically symmetric black hole in the non-reduced Einstein-Aether theory. It is shown that real oscillation frequency and damping rate are…
In this work, we construct an exact spherically symmetric black hole solution with a global monopole in the context of four-dimensional noncommutative Einstein-Gauss-Bonnet gravity. We modeled the spacetime noncommutativity via a…
A key test of any quantum theory of gravity is its ability to reproduce the known thermodynamic properties of black holes. A statistical mechanical description of the Bekenstein-Hawking entropy once seemed remote, but today we suffer an…
We address the question whether or not two electrically charged elementary particles can Coulomb scatter if one of these particles is inside the Schwarzschild black-hole horizon and the other outside. It can be shown that the quantum…
In this article, the question of the nature of cold dark matter is approached from a new angle. By invoking the Cauchy problem of relativity it is shown how, under very precise astrophysical conditions, the Einstein general theory of…
In this work we generalize the results for the entropy spectra typically derived for black holes in general relativity to a generic horizon within the spherically symmetric (asymptotically flat and non-flat) space-times of more general…
Einstein's general theory of relativity poses many problems to the quantum theory of point particle fields. Among them is the fate of a massive point particle. Since its rest mass exists entirely within its Schwarzschild radius, in the…
We study the black hole solution and gravitational wave polarizations in a M-subset of the Einstein-aether theory with Lorentz invariance violated by an unit norm vector field -- the aether field $u^a$. This M-subset of Einstein-aether…
We consider the evolution of self-gravitating matter fields that may undergo phase transitions, and we connect ideas from phase transition dynamics with concepts from bouncing cosmology. Our framework introduces scattering maps prescribed…
The space of the solutions of the differential equations resulting from considering matter fluids of scalar field type or perfect fluid in Einstein-aether theory is analyzed. The Einstein-aether theory of gravity consists of General…
We investigate the ultraviolet (UV) behavior of two-scalar elastic scattering with graviton exchanges in higher curvature gravity theory. In the Einstein gravity, matter scattering is shown not to satisfy tree unitarity at high energy.…
While the robustness of Hawking radiation in the presence of UV Lorentz breaking is well-established, the Unruh effect has posed a challenge, with a large literature concluding that even the low-energy restoration of Lorentz invariance may…
The Standard Model of particle physics predicts the speed of light to be a universal speed of propagation of massless carriers. However, other possibilities exist -- including Lorentz-violating theories -- where different fundamental fields…
We study anti-de Sitter black holes in the Einstein-Gauss-Bonnet and the generic R^2 gravity theories, evaluate different thermodynamic quantities, and also examine the possibilities of Hawking-Page type thermal phase transitions in these…