Related papers: Are Black Holes Elementary Particles?
Because of the very definition of black holes --- no light escapes them and falling objects get infinitely faint when approaching --- it is impossible to ever prove that they exist. However, electromagnetic and gravitational-wave…
Quantum entanglement lies at the heart of quantum information theory, with applications to quantum computing, teleportation, cryptography and communication. In the apparently separate world of quantum gravity, the Hawking effect of…
We use exact results in a new approach to quantum gravity to discuss some issues in black hole physics.
The dimensionless entropy, ${\cal S} \equiv S/k$, of the visible universe, taken as a sphere of radius 50 billion light years with the Earth at its "center", is discussed. An upper limit ($10^{112}$), and a lower limit ($10^{102}$), for…
We show that black holes can be quantized in an intuitive and elegant way with results in agreement with conventional knowledge of black holes by using Bohr's idea of quantizing the motion of an electron inside the atom in quantum…
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…
If the cosmological dark matter is primarily in the form of an elementary particle which has cross section and mass for self-interaction having a ratio similar to that of ordinary nuclear matter, then seed black holes (formed in stellar…
About one-fourth of the universe is thought to consist of dark matter. Yet there is no clear understanding about the nature of these particles. Commonly discussed dark matter candidates includes the so called WIMPs or weakly interacting…
Too light primordial black holes evaporate and are therefore strongly constrained by various bounds, e.g. Cosmic Microwave Background distortion. However, if they are formed strongly clustered, the corresponding haloes may collapse in…
The idea that gravity can act as a regulator of ultraviolet divergences is almost a century old and has inspired several approaches to quantum gravity. In fact, a minimum Planckian length can be shown to emerge from the nonlinear dynamics…
Over the past 15 years models with large extra space-time dimensions have been extensively studied. We have learned from these models that the energy scale of quantum gravity may be many orders of magnitude smaller than the conventional…
Primordial Black Holes (PBHs) are of interest in many cosmological contexts. PBHs lighter than about 1012 kg are predicted to be directly detectable by their Hawking radiation. This radiation should produce both a diffuse extragalactic…
If TeV-scale gravity describes nature, black holes will be produced in particle accelerators, perhaps even with impressive rates at the Large Hadron Collider. Their decays, largely via the Hawking process, will be spectacular. Black holes…
Cosmological and astrophysical measurements indicate that the universe contains a large amount of dark matter. A number of weak scale dark matter candidates have been proposed in extensions of the standard model. The potential to discover…
The horizon is a classical concept that arises in general relativity, and is therefore not clearly defined when the source cannot be reliably described by classical physics. To any (sufficiently) localised quantum mechanical wave-function,…
While extreme black hole spacetimes with smooth horizons are known at the level of mathematics, we argue that the horizons of physical extreme black holes are effectively singular. Test particles encounter a singularity the moment they…
Massive black holes are ubiquitous, occurring at the centres of all massive galaxies and possibly many low mass ones. They are no ornament which just happens to be there, but play a role vital to the growth and structure of the host galaxy.…
The quantum genesis of Hawking radiation is a long-standing puzzle in black hole physics. Semi-classically one can argue that the spectrum of radiation emitted by a black hole look very much sparse unlike what is expected from a thermal…
A spinning black hole with a much smaller black hole companion forms a fundamental gravitational system, like a colossal classical analog to an atom. In an appealing if imperfect analogy to atomic physics, this gravitational atom can be…
Relying solely on unitarity and the consistency with large-distance black hole physics, we derive model-independent properties of the microscopic black holes and of short-distance gravity in theories with N particle species. In this class…