Related papers: Maximum force and cosmic censorship
Stationary axisymmetric magnetic fields are expelled from outer horizons of black holes as they become extremal. Extreme black holes exhibit Meissner effect also within exact Einstein--Maxwell theory and in string theories in higher…
The thermodynamics and weak cosmic censorship conjecture in extended phase spaces of charged anti-de Sitter black holes describing the massive gravity are investigated by the absorptions of the scalar particle and fermion. The cosmological…
We consider stationary axially symmetric black holes with the background scalar field and test particles that can interact with this field directly. Then, particle collision near a black hole can lead to the unbounded energy $% E_{c.m.}$ in…
We argue that a black hole can be viewed as a gravitational optical element that images its interior onto the horizon. Being diffraction limited the "Airy hyper-ball" that forms as a result of interference of gravitational waves, does not…
We show that thermodynamics for an asymptotically flat Schwarzschild black hole leads to a force of magnitude $c^4/(2G)$. This remains true if one considers the simplest form of correction due to the generalized uncertainty principle. We…
It has been claimed that extreme black holes exhibit a phenomenon of flux expulsion for abelian Higgs vortices, irrespective of the relative width of the vortex to the black hole. Recent work by two of the authors showed a subtlety in the…
The interplay between cosmological expansion and local attraction in a gravitationally bound system is revisited in various regimes. First, weakly gravitating Newtonian systems are considered, followed by various exact solutions describing…
Using the result obtained in a prevoius paper, in which I found an upper limit on the region of particle creation in the vicinity of the event horizon of a Schwarzschild black hole, and by assuming that all the created energy will be…
Stupendously large black holes exceeding $10^{11} M_\odot$ could exist, supported by recent observations of unexpectedly massive black holes at high redshifts. These objects may constitute a part of dark matter or even dark energy. One…
We give a brief overview of black-hole solutions in four-dimensional supergravity theories and their extremal and supersymmetric limits. We also address problems like cosmic censorship and no-hair theorems in supergravity theories. While…
It has been shown that a nearly extremal black hole can be overcharged or overspun by a test particle if radiative and self-force effects are neglected, indicating that the cosmic censorship might fail. In contrast, the existing evidence in…
There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This paper looks at the limitations placed on these thought experiments by the null energy…
Black holes are perhaps the most strange and fascinating objects known to exist in the universe. Our understanding of space and time is pushed to its limits by the extreme conditions found in these objects. They can be used as natural…
Jacobson and Sotiriou showed that rotating black holes could be spun-up past the extremal limit by the capture of non-spinning test bodies, if one neglects radiative and self-force effects. This would represent a violation of the Cosmic…
The aim of the paper is the consideration of particle collisions in the vicinity of the horizon of rotating black holes. Existence of geodesics for massive and massless particles arising from the region inside of the gravitational radius in…
This essay reviews some of the recent progress in the area of energy conditions and wormholes. Most of the discussion centers on the subject of ``quantum inequality'' restrictions on negative energy. These are bounds on the magnitude and…
Recently, it was argued in [Phys. Rev. Lett. {\bf126}, 031102 (2021)] that the WCCC can serve as a constraint to high-order effective field theories. However, we find there exists a key error in their approximate black hole solution. After…
The spherical symmetry Black holes are considered in expanding background. The singularity line and the marginally trapped tube surface behavior are discussed. In particular, we address the conditions of whether a dynamical horizon forms…
We explore possible effects of vacuum energy on the evolution of black holes. If the universe contains a cosmological constant, and if black holes can absorb energy from the vacuum, then black hole evaporation could be greatly suppressed.…
Besides having some very interesting perturbatively unstable orbits, it seems that for a Schwarzschild black hole, below $r=3M$, the force always increases inward with increasing angular momentum. Here this previously known result is…