相关论文: Scattering of a Long Cosmic String by a Rotating B…

It has been suggested that amplitudes for quantum higher-spin massive particles exchanging gravitons lead, via a classical limit, to results for scattering of spinning black holes in general relativity, when the massive particles are in a…

The increasing interest in compact astrophysical objects (neutron stars, binaries, galactic black holes) has stimulated the search for rigorous methods, which allow a systematic general relativistic description of such objects. This paper…

Cosmic strings that are attached to rapidly spinning black holes can extract significant amounts of rotational energy and angular momentum. Here we study the effect on primordial black holes, which are expected to form with one or more…

We study the gravi-dilaton field of a Schwarzschild black hole pierced by a thin cosmic string in both massless and massive dilatonic gravity. We conclude that in the thin vortex approximation the string's spacetime is asymptotically flat…

Cosmic strings appear in many well-motivated extensions to the standard model of particle physics. If they exist, an abundant population of compact objects known as cosmic string loops permeate the Universe at all times, providing a…

We discuss non-relativistic scattering by a Newtonian potential. We show that the gray-body factors associated with scattering by a black hole exhibit the same functional dependence as scattering amplitudes in the Newtonian limit, which…

An accelerating observer sees a thermal bath of radiation at the Hawking temperature which is proportional to the acceleration. Also, in string theory there is a Hagedorn temperature beyond which one cannot go without an infinite amount of…

Traversable wormholes and regular black holes usually represent completely different scenarios. But in the black bounce spacetime they can be described by a same line element, which is very attractive. Furthermore, the black hole photos…

In this work we have studied the scattering of scalar field around an extended black hole in F(R) gravity using WKB method. We have obtained the wave function in different regions such as near the horizon region, away from horizon and far…

In 4D general relativity, the angular momentum of a black hole is limited by the Kerr bound. We suggest that in string theory, this bound can be breached and compact black-hole-like objects can spin faster. Near such "superspinars," the…

We study the dynamics of a cosmic string loop captured by a rotating black hole, ignoring string reconnections. A loop is numerically evolved in Kerr spacetime, with the result that it turns into one or more growing or contracting…

In this paper, some dynamical properties of neutral and charged particles around a weakly magnetized five-dimensional static black string have been studied. The perturbation method was also used to calculate the Innermost Stable Circular…

The scattering of charged massive scalar waves by Kerr-Newman black holes, with incidence along the equatorial plane, is investigated in this work. The differential scattering cross section is computed using the partial wave method, with…

By using semi-analytical method,we investigate the transmission and reflection coefficient and absorption and scattering cross section of spin 0,1,2 particles which are massless from a charged non rotating black holes. Here orbiting…

We analyze the scalar radiation emitted from a source rotating around a Schwarzschild black hole using the framework of quantum field theory at the tree level. We show that for relativistic circular orbits the emitted power is about 20% to…

The scattering of massless waves of helicity $|h|=0,\frac{1}{2},1$ in Schwarzschild and Kerr backgrounds is revisited in the long-wavelenght regime. Using a novel description of such backgrounds in terms of gravitating massive particles, we…

It is shown that the scattering of a charged test particle by a system of four extreme Reissner-Nordtr\"om black holes is chaotic in some cases. The fractal structure of the scattering angle and time delay functions is another manifestation…

The ultrarelativistic limit of the Kerr - Newman geometry is studied in detail. We find the gravitational shock wave background associated with this limit. We study the scattering of scalar fields in the gravitational shock wave geometries…

The one-loop contribution to the entropy of a black hole from field modes near the horizon is computed in string theory. It is modular invariant and ultraviolet finite. There is an infrared divergence that signifies an instability near the…

We model the light-curves from radiation-driven clouds near an accreting black hole. Taking into account the multiple images due to strong gravitational lensing, we find that sharp spikes can significantly enhance the observed flux.…