Related papers: Composite black holes in external fields
Recent results show that important singularities in General Relativity can be naturally described in terms of finite and invariant canonical geometric objects. Consequently, one can write field equations which are equivalent to Einstein's…
It is argued that the qualitative features of black holes, regarded as quantum mechanical objects, depend both on the parameters of the hole and on the microscopic theory in which it is embedded. A thermal description is inadequate for…
Motivated by theoretical and observational developments of cosmological coupled black holes, we construct an exact analytical solution for a black hole immersed in an anisotropic dark sector background, adopting the framework established by…
The existence of supermassive collapsed objects in the cores of most galaxies poses still-unanswered questions. First, how did they form, and how does their mass depend on the properties of the host galaxy? Second, can observations probe…
In this paper, we study the physical properties of black holes in the framework of the recently proposed Einstien-Bel-Robinson gravity. We show that interestingly the theory propagates a transverse and massive graviton on a maximally…
Black holes appear as vacuum solutions of classical general relativity which depend on Newton's constant and possibly the cosmological constant. At the level of a quantum field theory, these coupling constants typically acquire a…
We reconsider entropy of black holes which do not have finite area horizon. It is suggested that some of them should have nonzero entropy from both supergravity and string theory point of view. We also refine our arguments in our previous…
Four and five dimensional extremal black holes with nonzero entropy have simple presentations in M-theory as gravitational waves bound to configurations of intersecting M-branes. We discuss realizations of these objects in matrix models of…
General relativity has passed all solar system experiments and neutron star based tests, such as binary pulsar observations, with flying colors. A more exotic arena for testing general relativity is in systems that contain one or more black…
We study black hole solutions in an extension of General Relativity (GR) with an explicit non-minimal coupling between matter and curvature. General black hole solutions satisfying the known energy conditions are derived including the ones…
Black holes are among the most well-known astrophysical objects, yet their physical realisation remains conceptually subtle. We analyse physical black holes -- light-trapping regions that form in finite time as seen by a distant observer --…
5-dimensional Einstein-Maxwell-Chern-Simons theory with Chern-Simons coefficient $\lambda=1$ has supersymmetric black holes with vanishing horizon angular velocity, but finite angular momentum. Here supersymmetry is associated with a…
Fundamental fields are a natural outcome in cosmology and particle physics and might therefore serve as a proxy for more complex interactions. The equivalence principle implies that all forms of matter gravitate, and one therefore expects…
We construct asymptotically flat, static spherically symmetric black holes with regular centre in $f(R,T)$ gravity coupled to nonlinear electrodynamics Lagrangian. We obtain generalized metric function of the Bardeen and Hayward black…
We study geometrical structures of charged static black holes in the five-dimensional Einstein-Maxwell theory. The black holes we study have horizons in the form of squashed $ {\rm S}^3$, and their asymptotic structure consists of a twisted…
Two particles can collide inside a nonextremal black hole in such a way that the energy E_{c.m.} in their centre of mass frame becomes as large as one likes. We show that this effect can be understood with the help of a simple analogy with…
We address questions regarding construction and implications of gauge-invariant "dressed" observables in nontrivial background geometries such as that of a black hole. Formally, such observables can be constructed, e.g. by locating points…
We discuss and compare definitions of a black hole based on the existence of event and apparent horizons. In this connection we present a non-singular model of a black hole with a closed apparent horizon and discuss its properties. We…
We consider mixed strongly gravitating configurations consisting of a wormhole threaded by two types of ordinary matter. For such systems, the possibility of obtaining static spherically symmetric solutions describing compact massive…
We review some aspects of the attractor mechanism for extremal black holes of (not necessarily supersymmetric) theories coupling Einstein gravity to scalars and Maxwell vector fields. Thence, we consider N=2 and N=8, d=4 supergravities,…