141,605 research outputs found
Dirty Black Holes and Hairy Black Holes
An approach based on considerations of the non-classical energy momentum
tensor outside the event horizon of a black hole provides additional physical
insight into the nature of discrete quantum hair on black holes and its effect
on black hole temperature. Our analysis both extends previous work based on the
Euclidean action techniques, and corrects an omission in that work. We also
raise several issues related to the effects of instantons on black hole
thermodynamics and the relation between these effects and results in two
dimensional quantum field theory.Comment: 13 pages, Latex, submitted to Physical Review Letter
The Role of Primordial Kicks on Black Hole Merger Rates
Primordial stars are likely to be very massive \geq30\Msun, form in
isolation, and will likely leave black holes as remnants in the centers of
their host dark matter halos in the mass range
10^{6}-10^{10}\Ms. Such early black holes, at redshifts z\gtsim10, could
be the seed black holes for the many supermassive black holes found in galaxies
in the local universe. If they exist, their mergers with nearby supermassive
black holes may be a prime signal for long wavelength gravitational wave
detectors. We simulate formation of black holes in the center of high redshift
dark matter halos and explore implications of initial natal kick velocities
conjectured by some formation models. The central concentration of early black
holes in present day galaxies is reduced if they are born even with moderate
kicks of tens of km/s. The modest kicks allow the black holes to leave their
parent halo, which consequently leads to dynamical friction being less
effective on the lower mass black holes as compared to those still embedded in
their parent halos. Therefore, merger rates may be reduced by more than an
order of magnitude. Using analytical and illustrative cosmological N--body
simulations we quantify the role of natal kicks of black holes formed from
massive metal free stars on their merger rates with supermassive black holes in
present day galaxies. Our results also apply to black holes ejected by the
gravitational slingshot mechanism.Comment: 12 pages, 9 figure
Holographic complexity of Born-Infeld black holes
In this paper, according to CA duality, we study complexity growth of
Born-Infeld (BI) black holes. As a comparison, we study action growth of dyonic
black holes in Einstein-Maxwell gravity at the beginning. We study action
growth of electric BI black holes in dRGT massive gravity, and find BI black
holes in massive gravity complexify faster than the Einstein gravity
counterparts. We study action growth of the purely electric and magnetic
Einstein-Born-Infeld (EBI) black holes in general dimensions and the dyonic EBI
black holes in four-dimensions, and find the manners of action growth are
different between electric and magnetic EBI black holes. In all the gravity
systems we considered, we find action growth rates vanish for the purely
magnetic black holes, which is unexpected. In order to ameliorate the
situation, we add the boundary term of matter field to the action and discuss
the outcomes of the addition.Comment: 26 pages, 6 figur
Large rotating AdS black holes from fluid mechanics
We use the AdS/CFT correspondence to argue that large rotating black holes in
global AdS(D) spaces are dual to stationary solutions of the relativistic
Navier-Stokes equations on S**(D-2). Reading off the equation of state of this
fluid from the thermodynamics of non-rotating black holes, we proceed to
construct the nonlinear spinning solutions of fluid mechanics that are dual to
rotating black holes. In all known examples, the thermodynamics and the local
stress tensor of our solutions are in precise agreement with the thermodynamics
and boundary stress tensor of the spinning black holes. Our fluid dynamical
description applies to large non-extremal black holes as well as a class of
large non-supersymmetric extremal black holes, but is never valid for
supersymmetric black holes. Our results yield predictions for the
thermodynamics of all large black holes in all theories of gravity on AdS
spaces, for example, string theory on AdS(5) x S**5 and M theory on AdS(4) x
S**7 and AdS(7) x S**4.Comment: 62 pages, 1 figure. v2: references, typo
Phantom Energy Accretion onto Black Holes in Cyclic Universe
Black holes pose a serious problem in the cyclic or oscillating cosmology. It
is speculated that, in the cyclic universe with phantom turnarounds, black
holes will be torn apart by the phantom energy before turnaround before they
can create any problems. In this paper, using the mechanism of the phantom
accretion onto black holes, we find that black holes do not disappear before
the phantom turnaround. But the remanent black holes will not cause any
problems due to the Hawking evaporation.Comment: 8 pages, no figure; typographical errors are correcte
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