144 research outputs found
Initiating the effective unification of black hole horizon area and entropy quantization with quasi-normal modes
Black hole (BH) quantization may be the key to unlocking a unifying theory of
quantum gravity (QG). Surmounting evidence in the field of BH research
continues to support a horizon (surface) area with a discrete and uniformly
spaced spectrum, but there is still no general agreement on the level spacing.
In this specialized and important BH case study, our objective is to report and
examine the pertinent groundbreaking work of the strictly thermal and
non-strictly thermal spectrum level spacing of the BH horizon area quantization
with included entropy calculations, which aims to tackle this gigantic problem.
In particular, this work exemplifies a series of imperative corrections that
eventually permits a BH's horizon area spectrum to be generalized from strictly
thermal to non-strictly thermal with entropy results, thereby capturing
multiple preceding developments by launching an effective unification between
them. Moreover, the identified results are significant because quasi-normal
modes (QNM) and "effective states" characterize the transitions between the
established levels of the non-strictly thermal spectrum.Comment: 23 pages, review paper. Final version to appear in Advances in High
Energy Physic
Charged Black Holes in Einsteinian Quartic Gravity
In this paper, we studied Einsteinian quartic gravity minimally coupled to
electrodynamics in four dimensions. First, by variation action, we obtain the
field equations, and by integration, we obtain a nonlinear third-order
differential equation for the metric function and as well as the
electromagnetic potential. Then, in the context of the Maxwell field, we
discussed the conditions under which the charged black hole exists. Then, we
have demonstrated the thermodynamics and stability of the solution for the case
of positive coupling of quartic theory. Finally, we showed that the charged
black hole solutions of EQG (unlike GR and like ECG) have no inner horizon and
do not conform to the extremal bound of GR. Also, the uniqueness of BH
solutions in this theory does not work anymore.Comment: 13 pages, 6 figure
Topological Black Holes in Lovelock-Born-Infeld Gravity
In this paper, we present topological black holes of third order Lovelock
gravity in the presence of cosmological constant and nonlinear electromagnetic
Born-Infeld field. Depending on the metric parameters, these solutions may be
interpreted as black hole solutions with inner and outer event horizons, an
extreme black hole or naked singularity. We investigate the thermodynamics of
asymptotically flat solutions and show that the thermodynamic and conserved
quantities of these black holes satisfy the first law of thermodynamic. We also
endow the Ricci flat solutions with a global rotation and calculate the finite
action and conserved quantities of these class of solutions by using the
counterterm method. We compute the entropy through the use of the Gibbs-Duhem
relation and find that the entropy obeys the area law. We obtain a Smarr-type
formula for the mass as a function of the entropy, the angular momenta, and the
charge, and compute temperature, angular velocities, and electric potential and
show that these thermodynamic quantities coincide with their values which are
computed through the use of geometry. Finally, we perform a stability analysis
for this class of solutions in both the canonical and the grand-canonical
ensemble and show that the presence of a nonlinear electromagnetic field and
higher curvature terms has no effect on the stability of the black branes, and
they are stable in the whole phase space.Comment: 14 page
Rotating Black Branes in the presence of nonlinear electromagnetic field
In this paper, we consider a class of gravity whose action represents itself
as a sum of the usual Einstein-Hilbert action with cosmological constant and an
gauge field for which the action is given by a power of the Maxwell
invariant. We present a class of the rotating black branes with Ricci flat
horizon and show that the presented solutions may be interpreted as black brane
solutions with two event horizons, extreme black hole and naked singularity
provided the parameters of the solutions are chosen suitably. We investigate
the properties of the solutions and find that for the special values of the
nonlinear parameter, the solutions are not asymptotically anti-deSitter. At
last, we obtain the conserved quantities of the rotating black branes and find
that the nonlinear source effects on the electric field, the behavior of
spacetime, type of singularity and other quantities.Comment: 7 pages, 5 figures, to appear in EPJ
Stringy Stability of Charged Dilaton Black Holes with Flat Event Horizon
Electrically charged black holes with flat event horizon in anti-de Sitter
space have received much attention due to various applications in Anti-de
Sitter/Conformal Field Theory (AdS/CFT) correspondence, from modeling the
behavior of quark-gluon plasma to superconductor. Crucial to the physics on the
dual field theory is the fact that when embedded in string theory, black holes
in the bulk may become vulnerable to instability caused by brane
pair-production. Since dilaton arises naturally in the context of string
theory, we study the effect of coupling dilaton to Maxwell field on the
stability of flat charged AdS black holes. In particular, we study the
stability of Gao-Zhang black holes, which are locally asymptotically anti-de
Sitter. We find that for dilaton coupling parameter > 1, flat black
holes are stable against brane pair production, however for 0 < < 1,
the black holes eventually become unstable as the amount of electrical charges
is increased. Such instability however, behaves somewhat differently from that
of flat Reissner-Nordstr\"om black holes. In addition, we prove that the
Seiberg-Witten action of charged dilaton AdS black hole of Gao-Zhang type with
flat event horizon (at least in 5-dimension) is always logarithmically
divergent at infinity for finite values of , and is finite and positive
in the case tends to infinity . We also comment on the robustness of
our result for other charged dilaton black holes that are not of Gao-Zhang
type.Comment: Fixed some confusions regarding whether part of the discussions
concern electrically charged hole or magnetically charged one. No changes to
the result
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