Related papers: You Cannot Press Out the Black Hole

We show that neither accretion nor angular momentum extraction are likely to lead to significant changes in the mass M_1 or angular momentum parameter a_* of a black hole in a binary system with realistic parameters. Current values of M_1…

Using a smooth triangulation and a Riemannian metric on a compact, connected, closed manifold M of dimension n we have got that every such M can be represented as a union of a n-dimensional cell and a connected union K of some subsimplexes…

There is a growing literature on dyonic black holes as they appear in string theory. Here we examine the correspondence limit of a dyonic black hole which is not supersymmetric. Assuming the existence of a dyon with non-supersymmetric…

I demonstrate that, under certain circumstances, regions of negative energy density can undergo gravitational collapse into a black hole. The resultant exterior black hole spacetimes necessarily have negative mass and non-trivial topology.…

A simple criterion is given to rule out the existence of closed trapped surfaces in large open regions inside black holes.

A new class of vacuum black holes for the most general gravity theory leading to second order field equations in the metric in even dimensions is presented. These space-times are locally AdS in the asymptotic region, and are characterized…

The traditional black hole has a horizon, with a singularity inside the horizon. But actual microstates of black holes are `fuzzballs', with no horizon and a complex internal structure. We take the simplest hole in string theory -- the…

If one surrounds a black hole with a perfectly reflecting shell and adiabatically squeezes the shell inward, one can increase the black hole area A to exceed four times the total entropy S, which stays fixed during the process. A can be…

Recently, there has been a lot of interest in Carroll black holes and in particular whether or not one could find a Carrollian analogue of a rotating black hole spacetime. Here we show that every stationary and axisymmetric solution (and…

Regular (non-singular) space-times are given which describe the formation of a (locally defined) black hole from an initial vacuum region, its quiescence as a static region, and its subsequent evaporation to a vacuum region. The static…

In this work we attempt to overcharge extremal and nearly extremal charged black holes in string theory, known as the Garfinkle-Horowitz-Strominger solution. We first show that extremal black holes cannot be overcharged analogous to the…

In general relativity without a cosmological constant, a classical theorem due to Hawking states that stationary black holes must be topologically spherical. This result is one of the several ingredients that collectively imply the…

A family of spacetimes suitable for describing the interior of a non-rotational black hole is constructed. The stress-energy tensor is that of a spherically symmetric vacuum, as commonly assumed nowadays. The problem of matching the…

Generic $U(1)^2$ 4-d black holes with unbroken $N=1$ supersymmetry are shown to tend to a Robinson-Bertotti type geometry with a linear dilaton and doubling of unbroken supersymmetries near the horizon. Purely magnetic dilatonic black…

Static spherically symmetric black hole solution is obtained in the framework of Einstein-dilaton theory with nonlinear Maxwell and Yang-Mills fields of power-law type. It is observed that black hole might have two horizons similarly as it…

We demonstrate that the isentropic absorption of a classical charged test particle is classically forbidden for all 3+1 dimensional stationary, non-extremal, axisymmetric black holes in any diffeomorphism invariant theory of gravity. This…

We have recently proposed a model for a regular black hole, or an ultra-compact object, that is premised on having maximally negative radial pressure throughout the entirety of the object's interior. This model can be viewed as that of a…

We investigate properties of the inner horizons of certain black holes in higher-derivative three-dimensional gravity theories. We focus on BTZ and Spacelike Warped Anti-de Sitter black holes, as well as on asymptotically Warped de-Sitter…

When a lump of matter falls into a black hole it is expected that a marginally trapped tube when hit moves outwards everywhere, even in regions not yet in causal contact with the infalling matter. But to describe this phenomenon…

We argue that black holes admit vortex structure. This is based both on a graviton-condensate description of a black hole as well as on a correspondence between black holes and generic objects with maximal entropy compatible with unitarity,…