Related papers: Lower bound on the mass of a black hole
Ultralight dark photons predicted in several Standard Model extensions can trigger the superradiant instability around rotating black holes if their Compton wavelength is comparable to the Blackhole radius. Consequently, the angular…
We present a semiclassical proof of the weak gravity conjecture in $D = 4$ spacetime dimensions for scalar matter gauged under a $U(1)^N$ gauge group. We compute the non-perturbative macroscopic entropy of a scalar field in an extremal…
We construct extremal, spherically symmetric black hole solutions to 4D supergravity with charge assignments that preclude BPS-saturation. In particular, we determine the ground state energy as a function of charges and moduli. We find that…
The rotational properties of astrophysical black holes are fundamental quantities that characterization the black holes. A new method to empirically determine the spin mass-energy characteristics of astrophysical black holes is presented…
We discuss the identity of black hole entropy and show that the first law of black hole thermodynamics, in the case of a Schwarzschild black hole, can be derived from Landauer's principle by assuming that the black hole is one of the most…
We outline a dynamical dark energy scenario whose signatures may be simultaneously tested by astronomical observations and laboratory experiments. The dark energy is a field with slightly sub-gravitational couplings to matter, a logarithmic…
There are reasons (which we enumerate) to think that an infinite extra dimension will harbor a black hole. In this case, brane-localized modes of gravity and gauge fields become quasilocalized, and light from a distant object can become…
Conventional general relativity supplies the notion of a vacuum tension and thus a maximum force $F_{max}=c^4/4G\approx\ 3\times 10^{43}$ Newtons, that is realized for a black hole. In conjunction with the Wilson area rule, we are thus led…
Particle radiation from black holes has an observed emission power depending on the surface gravity $\kappa = c^4/(4GM)$ as \begin{equation}\nonumber P_{\textrm{black hole}} \sim \frac{\hbar \kappa^2}{6\pi c^2} = \frac{\hbar c^6}{96\pi G^2…
We derive a relativistic field equation for the trace of the metric perturbation beyond the weak field approximation to the Einstein field equations. The dynamics is governed by a massive Klein-Gordon equation on curved space-time, where…
We consider unitary and weakly coupled theories of gravity that extend Einstein gravity and reduce to it asymptotically at large distances. Our discussion is restricted to such theories that, similarly to Einstein gravity, contain black…
I show that attempts to detect Hawking quanta would reduce the quantum state to one containing ultra-energetic incoming particles; couplings of these to other systems would extract ultra-high energies from the gravitational collapse. As the…
By a simple modification of Hawking's well-known topology theorems for black hole horizons, we find lower bounds for the areas of smooth apparent horizons and smooth cross-sections of stationary black hole event horizons of genus $g>1$ in…
Gravitational waves from the coalescence of binary black holes carry away linear momentum, causing center of mass recoil. This "radiation rocket" effect has important implications for systems with escape speeds of order the recoil velocity.…
The mass--energy formula of black holes implies that up to 50% of the energy can be extracted from a static black hole. Such a result is reexamined using the recently established analytic formulas for the collapse of a shell and expression…
We use the integrated spectrum of the X-ray background and quasars Spectral Energy Distribution to derive the contribution of quasars to the energy output of the Universe. We find a lower limit for the energy from accretion onto black holes…
The prospect of mini black holes, either primordial or in planned experiments at the Large Hadron Collider, interacting with the earth motivate us to examine how they may be detected and the scope of their impact on the earth. We propose…
We numerically investigate the imprints of gravitational radiation-reaction driven changes to a black hole's mass and spin on the corresponding ringdown waveform. We do so by comparing the dynamics of a perturbed black hole evolved with the…
Understanding the end state of black hole evaporation, the microscopic origin of black hole entropy, the information loss paradox, and the nature of the singularity arising in gravitational collapse - these are outstanding challenges for…
We study entropic force effects on black holes and photons. We find that application of an entropic analysis restricts the radial change $\Delta R$ of a black hole of radius $R_{\mathrm{H}}$, due to a test particle of a Schwartzchild radius…