Related papers: The Meissner effect for weakly isolated horizons
We show that extremal Kerr black holes are sensitive probes of new physics. Stringy or quantum corrections to general relativity are expected to generate higher-curvature terms in the gravitational action. We show that in the presence of…
Linear perturbations of extremal black holes exhibit the Aretakis instability, in which higher derivatives of a scalar field grow polynomially with time along the event horizon. This suggests that higher derivative corrections to the…
We numerically construct asymptotically anti-de Sitter (AdS) black holes in four dimensions that contain only a single Killing vector field. These solutions, which we coin black resonators, link the superradiant instability of Kerr-AdS to…
Massive merging black holes will be the primary sources of powerful gravitational waves at low frequency, and will permit to test general relativity with candidate galaxies close to a binary black hole merger. In this paper we identify the…
The massless scalar field in the higher-dimensional Kerr black hole (Myers- Perry solution with a single rotation axis) has been investigated. It has been shown that the field equation is separable in arbitrary dimensions. The quasi-normal…
Black holes are the simplest macroscopic objects, and provide unique tests of General Relativity. They have been compared to the Hydrogen atom in quantum mechanics. Here, we establish a few facts about the simplest systems bound by gravity:…
We consider a type I superconducting body that contains one or more holes in its interior that undergoes a transition between normal and superconducting states in the presence of a magnetic field. We argue that unlike other thermodynamic…
We show that in realistic cases of accretion in active galactic nuclei or stellar-mass X-ray binaries, the Lense-Thirring effect breaks the central regions of tilted accretion discs around spinning black holes into a set of distinct planes…
Accretion disks around black holes radiate a significant fraction of the rest mass of the accreting material in the form of thermal radiation from within a few gravitational radii of the black hole ($ r \lesssim 20 G M / c^{2}$). In…
Scattering of particles in the gravitational field of Kerr black holes is considered. It is shown that scattering energy of particles in the centre of mass system can obtain very large values not only for extremal black holes but also for…
In 4-dimensional General Relativity, black holes are described by the Kerr solution and are completely specified by their mass $M$ and by their spin angular momentum $J$. A fundamental limit for a black hole in General Relativity is the…
By using a quasi-stationary approach, we consider the mass evolution of Schwarzschild black holes in the presence of a nonminimally coupled cosmological scalar field. The mass evolution equation is analytically solved for generic coupling,…
Continuous sequences of asymptotically flat solutions to the Einstein-Maxwell equations describing regular equilibrium configurations of ordinary matter can reach a black hole limit. For a distant observer, the spacetime becomes more and…
Astrophysical black hole candidates are thought to be the Kerr black holes predicted by General Relativity, but the actual nature of these objects has still to be proven. The Kerr black hole hypothesis can be tested by observing strong…
Superconductivity occurs in systems that have a lot of negative charge: the highly negatively charged $(CuO2)^{--}$ planes in the cuprates, negatively charged $(FeAs)^-$ planes in the iron arsenides, and negatively charged $B^-$ planes in…
The ability of a plasma surrounding spinning black holes to extract rotational energy and power energetic emissions has been recognized as a key astrophysical phenomenon. Important insights into the nature of this process are obtained…
An exact solution representing black holes in an expanding universe is found. The black holes are maximally charged and the universe is expanding with arbitrary equation of state. It is an exact solution of the Einstein-scalar-Maxwell…
Numerous variations have been proposed on the original suggestion by Blandford and Znajek that magnetic fields could be used to extract rotational energy from black holes. A new categorization of these variations is proposed so that they…
If astrophysical black hole candidates are the Kerr black holes predicted by General Relativity, the value of their spin parameter must be subject to the theoretical bound $|a_*| \le 1$. In this work, we consider the possibility that these…
X-ray binary systems are very popular objects for astrophysical investigations. Compact objects in these systems are neutron stars, white dwarfs and black holes. Neutron stars and white dwarfs can have intrinsic magnetic fields. There is…