5 research outputs found
Apparent horizon formation in the head-on collision of gyratons
The gyraton model describes a gravitational field of an object moving with
the velocity of light which has finite energy and spin distributed during some
finite time interval . A gyraton may be considered as a classical toy model
for a quantum wave packet of high-energy particles with spin. In this paper we
study a head-on collision of two gyratons and black hole formation in this
process. The goal of this study is to understand the role of the gravitational
spin-spin interaction in the process of mini-black-hole formation in particle
collisions. To simplify the problem we consider several gyraton models with
special profiles of the energy and spin density distribution. For these models
we study the apparent horizon (AH) formation on the future edge of a spacetime
region before interaction. We demonstrate that the AH forms only if the energy
duration and the spin are smaller than some critical values, while the length
of the spin distribution should be at least of the order of the system
gravitational radius. We also study gravitational spin-spin interaction in the
head-on collision of two gyratons under the assumption that the values of
gyraton spins are small. We demonstrate that the metric in the interaction
region for such gyratons depends on the relative helicities of incoming
gyratons, and the collision of gyratons with oppositely directed spins allows
the AH formation in a larger parameter region than in the collision of the
gyratons with the same direction of spins. Some applications of the obtained
results to the mini-black-hole production at the Large Hadron Collider in TeV
gravity scenarios are briefly discussed.Comment: 44 pages, 21 figures, published versio
Canonical Quantization of the Electromagnetic Field on the Kerr Background
We investigate the canonical quantization of the electromagnetic field on the
Kerr background. We give new expressions for the expectation value of the
electromagnetic stress-energy tensor in various vacua states and give a
physical interpretation of the separate terms appearing in them. We numerically
calculate the luminosity in these states. We also study the form of the
renormalized stress-energy tensor close to the horizon when the electromagnetic
field is in the past Boulware state.Comment: 27 zipped, postscript figure file
Angular profile of emission of non-zero spin fields from a higher-dimensional black hole
Recent works have included the effect of rotation on simulations of black hole events at the LHC, showing that the angular momentum of the black hole cannot be ignored and it makes a non-trivial contribution for most of the lifetime of the black hole. A key consequence of the rotation of the black hole is that the Hawking radiation is no longer isotropic, making it more difficult to infer space–time parameters from measurements of the emitted particles. In this Letter we study the angular distribution of the Hawking emission of non-zero spin particles with specific helicity on the brane. We argue that the shape of the distribution could be used as a measure of the angular momentum of the black hole