相关论文: The Hoop Conjecture for Black Rings

A black hole considered as a part of a thermodynamical system possesses the Bekenstein-Hawking entropy $S_H =A_H /(4l_{\mbox{\scriptsize{P}}}^2)$, where $A_H$ is the area of a black hole surface and $l_{\,\mbox{\scriptsize{P}}}$ is the…

The Karlhede invariant is formed from the contraction of the covariant derivative of the Riemann tensor. It is a coordinate invariant that vanishes at the Schwarzschild event horizon $r=2m$. The vanishing of the invariant allows an observer…

It is known that the event horizon of a black hole can often be identified from the zeroes of some curvature invariants. The situation in lower dimensions has not been thoroughly clarified. In this work we investigate both (2+1)- and…

Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected…

In LQG, black hole horizons are described by 2+1 dimensional boundaries of a bulk 3+1 dimensional spacetime. The horizon is endowed with area by lines of gravitational flux which pierce the surface. As is well known, counting of the…

In this paper we characterize the intrinsic geometry of apparent horizons (outermost marginally outer trapped surfaces) in asymptotically flat spacetimes; that is, the Riemannian metrics on the two sphere which can arise. Furthermore we…

The existence of light rings in a spacetime is closely related to the existence of black hole horizons and observables such as the ringdown and the shadow. Black holes, compared to nonvacuum ultracompact objects, have rather unique…

The concept of black hole entropy is one of the most important enigmas of theoretical physics. It relates thermodynamics to gravity and allows substantial hints toward a quantum theory of gravitation. Although Bekenstein conjecture…

The dragging of inertial frames by an orbiting object implies that the horizon angular velocity $\Omega^{\text{BH-ring}}_{\text{H}}$ of a central black hole in a composed black-hole-orbiting-ring system is no longer related to its…

The no-short hair theorem for static spherically symmetric black holes in general theory of relativity asserts that if a black hole has hair, that hair must extend beyond the lowest photon sphere radius of the black hole. This report…

Four spherically symmetric but non-asymptotically flat black hole solutions surrounded with spherical dark matter distribution perceived under the minimal length scale effect is derived via the generalized uncertainty principle. Here, the…

We present new near-infrared (IR) observations of the H$\beta\ \lambda4861$ and MgII $\lambda2798$ lines for 32 luminous quasars with $3.2<z<3.9$ using the Palomar Hale 200 inch telescope and the Large Binocular Telescope. We find that the…

Thanks for the releasing image of supermassive black holes (BHs) by the event horizon telescope (EHT) at the heart of the $M87$ galaxy. After the discovery of this mysterious object, scientists paid attention to exploring the BH shadow…

Jet ejection by accreting black holes is a mass invariant mechanism unifying stellar and supermassive black holes (SMBHs) that should also apply for intermediate-mass black holes (IMBHs), which are thought to be the seeds from which SMBHs…

Symmergent gravity is the $R+R^2$ gravity theory which emerges in a way restoring gauge symmetries broken explicitly by the ultraviolet cutoff in effective field theories. To test symmergent gravity we construct novel black hole solutions…

Bekenstein-Hawking formalism of black hole thermodynamics should be modified to incorporate quantum gravitational effects. Generalized Uncertainty Principle(GUP) provides a suitable framework to perform such modifications. In this paper, we…

Bekenstein proposed that the spectrum of horizon area of quantized black holes must be discrete and uniformly spaced. We examine this proposal in the context of spherically symmetric charged black holes in a general class of gravity…

We propose a novel solution for the endpoint of gravitational collapse, in which spacetime ends (and is orbifolded) at a microscopic distance from black hole event horizons. This model is motivated by the emergence of singular event…

Questions about black holes in quantum gravity generally presuppose the presence of a horizon. Recently Carlip has shown that enforcing an initial data surface to be a horizon leads to the correct form for the Bekenstein-Hawking entropy of…

The exact formula derived by us earlier for the entropy of a four dimensional non-rotating black hole within the quantum geometry formulation of the event horizon in terms of boundary states of a three dimensional Chern-Simons theory, is…