55 research outputs found
Collision of Two Rotating Hayward Black Holes
We investigate the spin interaction and the gravitational radiation thermally
allowed in a head-on collision of two rotating Hayward black holes. The Hayward
black hole is a regular black hole in a modified Einstein equation, and hence
it can be an appropriate model to describe the extent to which the regularity
effect in the near-horizon region affects the interaction and the radiation. If
one black hole is assumed to be considerably smaller than the other, the
potential of the spin interaction can be analytically obtained and is dependent
on the alignment of angular momenta of the black holes. For the collision of
massive black holes, the gravitational radiation is numerically obtained as the
upper bound by using the laws of thermodynamics. The effect of the Hayward
black hole tends to increase the radiation energy, but we can limit the effect
by comparing the radiation energy with the gravitational waves GW150914 and
GW151226.Comment: 25 pages, 43 figures, published version in EPJ
Quasinormal Modes of Massive Scalar Field with Nonminimal Coupling in Higher-Dimensional de Sitter Black Hole with Single Rotation
We analytically investigate the quasinormal modes of the massive scalar field
with a nonminimal coupling in the higher-dimensional de Sitter black hole with
a single rotation. According to the separated scalar field equation, the
boundary conditions of quasinormal modes are well constructed at the outer and
cosmological horizons. Then, under near-extremal conditions, where the outer
horizon closes to the cosmological horizon, the quasinormal frequencies are
obtained and generalized to universal form in the higher-dimensional spacetime.
Here, the real part of the frequency includes the scalar field contents, and
its imaginary part only depends on the surface gravity at the outer horizon of
the black hole.Comment: 14 pages, 4 figures, published in EPJ
Weak Cosmic Censorship Conjecture in Kerr-(Anti-)de Sitter Black Hole with Scalar Field
We investigate the weak cosmic censorship conjecture in Kerr-(anti-)de Sitter
black holes under the scattering of a scalar field. We test the conjecture in
terms of whether the black hole can exceed the extremal condition with respect
to its change caused by the energy and angular momentum fluxes of the scalar
field. Without imposing the laws of thermodynamics, we prove that the
conjecture is valid in all the initial states of the black hole (non-extremal,
near-extremal, and extremal black holes). The validity in the case of the
near-extremal black hole is different from the results of similar tests
conducted by adding a particle because the fluxes represent the energy and
angular momentum transferred to the black hole during the time interval not
included in the tests involving the particle. Using the time interval, we show
that the angular velocity of the black hole with the scalar field of a constant
state takes a long time for saturation to the frequency of the scalar field.Comment: 20 pages, 3 figures, published in JHE
Thermodynamics with Pressure and Volume under Charged Particle Absorption
We investigate the variation of the charged anti-de Sitter black hole under
charged particle absorption by considering thermodynamic volume. The variation
exactly corresponds to that expected as the first law of thermodynamics.
Nevertheless, we find the decrease of the Bekenstein-Hawking entropy for
extremal and near-extremal black holes under the absorption to be an
irreversible process. This violation of the second law of thermodynamics is
only found in the case considering thermodynamic volume. We test the weak
cosmic censorship conjecture affected by the violation. Fortunately, the
conjecture is still valid. However, extremal and near-extremal black holes do
not change their configurations under the absorption. This is quite different
from the case without thermodynamic volume.Comment: 14 pages, 5 figure
Strong Cosmic Censorship under Quasinormal Modes of Non-Minimally Coupled Massive Scalar Field
We investigate the strong cosmic censorship conjecture in lukewarm
Reissner-Nordstr\"{o}m-de Sitter black holes (and Mart\'{i}nez-Troncoso-Zanelli
black holes) using the quasinormal resonance of non-minimally coupled massive
scalar field. The strong cosmic censorship conjecture is closely related to the
stability of the Cauchy horizon governed by the decay rate of the dominant
quasinormal mode. Here, dominant modes are obtained in the limits of small and
large mass black holes. Then, we connect the modes by using the WKB
approximation. In our analysis, the strong cosmic censorship conjecture is
valid except in the range of the small-mass limit, in which the dominant mode
can be assumed to be that of the de Sitter spacetime. Particularly, the
coupling constant and mass of the scalar field determine the decay rate in the
small mass range. Therefore, the validity of the strong cosmic censorship
conjecture depends on the characteristics of the scalar field.Comment: 19 pages, 10 figures, published in EPJ
Thermodynamics of Three-dimensional Black Holes via Charged Particle Absorption
We have shown that changes occur in a (2+1)-dimensional charged black hole by
adding a charged probe. The particle increases the entropy of the black hole
and guarantees the second law of thermodynamics. The first law of
thermodynamics is derived from the change in the black hole mass. Using the
particle absorption, we test the extremal black hole and find out that the mass
of the extremal black hole increases more than the electric charge. Therefore,
the outer horizon of the black hole still exists. However, the extremal
condition becomes non-extremal.Comment: 6 page
Weak Cosmic Censorship Conjecture in Myers-Perry Black Hole with Separability
We investigate the weak cosmic censorship conjecture in Myers-Perry black
holes with arbitrary rotations in general dimensions based on the scattering of
a massless scalar field. From the fluxes of the scalar field flowing into the
black hole, the changes in mass and angular momenta of the black hole are
obtained. However, the extremal and near-extremal black holes with the
aforementioned changes are still black holes in the final state. Hence, the
conjecture is valid for our investigation. Furthermore, we analyze the changes
in the black hole from a thermodynamic perspective to highlight that the laws
of thermodynamics support the conjecture.Comment: 17 pages, 3 figure
- …