40 research outputs found

### A Non-relativistic Logarithmic Conformal Field Theory from a Holographic Point of View

We study a fourth-order derivative scalar field configuration in a fixed
Lifshitz background. Using an auxiliary field we rewrite the equations of
motion as two coupled second order equations. We specialize to the limit that
the mass of the scalar field degenerates with that of the auxiliary field and
show that logarithmic modes appear. Using non-relativistic holographic methods
we calculate the two-point correlation functions of the boundary operators in
this limit and find evidence for a non-relativistic logarithmic conformal field
theory at the boundary.Comment: 17 pages, v2 : refs. adde

### Kerr-CFT From Black-Hole Thermodynamics

We analyze the near-horizon limit of a general black hole with two commuting
killing vector fields in the limit of zero temperature. We use black hole
thermodynamics methods to relate asymptotic charges of the complete spacetime
to those obtained in the near-horizon limit. We then show that some
diffeomorphisms do alter asymptotic charges of the full spacetime, even though
they are defined in the near horizon limit and, therefore, count black hole
states. We show that these conditions are essentially the same as considered in
the Kerr/CFT corresponcence. From the algebra constructed from these
diffeomorphisms, one can extract its central charge and then obtain the black
hole entropy by use of Cardy's formula.Comment: 19 pages, JHEP3, no figures. V2: References added, small typos fixe

### A de Sitter Hoedown

Rotating black holes in de Sitter space are known to have interesting limits
where the temperatures of the black hole and cosmological horizon are equal. We
give a complete description of the thermal phase structure of all allowed
rotating black hole configurations. Only one configuration, the rotating Nariai
limit, has the black hole and cosmological horizons both in thermal and
rotational equilibrium, in that both the temperatures and angular velocities of
the two horizons coincide. The thermal evolution of the spacetime is shown to
lead to the pure de Sitter spacetime, which is the most entropic configuration.
We then provide a comprehensive study of the wave equation for a massless
scalar in the rotating Nariai geometry. The absorption cross section at the
black hole horizon is computed and a condition is found for when the scattering
becomes superradiant. The boundary-to-boundary correlators at finite
temperature are computed at future infinity. The quasinormal modes are obtained
in explicit form. Finally, we obtain an expression for the expectation value of
the number of particles produced at future infinity starting from a vacuum
state with no incoming particles at past infinity. Some of our results are used
to provide further evidence for a recent holographic proposal between the
rotating Nariai geometry and a two-dimensional conformal field theory.Comment: 35 + 1 pages, 9 figures; v3: typos correcte

### Holography at an Extremal De Sitter Horizon

Rotating maximal black holes in four-dimensional de Sitter space, for which
the outer event horizon coincides with the cosmological horizon, have an
infinite near-horizon region described by the rotating Nariai metric. We show
that the asymptotic symmetry group at the spacelike future boundary of the
near-horizon region contains a Virasoro algebra with a real, positive central
charge. This is evidence that quantum gravity in a rotating Nariai background
is dual to a two-dimensional Euclidean conformal field theory. These results
are related to the Kerr/CFT correspondence for extremal black holes, but have
two key differences: one of the black hole event horizons has been traded for
the cosmological horizon, and the near-horizon geometry is a fiber over dS_2
rather than AdS_2.Comment: 15 page

### The Entropy for General Extremal Black Holes

We use the Kerr/CFT correspondence to calculate the entropy for all known
extremal stationary and axisymmetric black holes. This is done with the help of
two ansatzs that are general enough to cover all such known solutions.
Considering only the contribution from the Einstein-Hilbert action to the
central charge(s), we find that the entropy obtained by using Cardy's formula
exactly matches with the Bekenstein-Hawking entropy.Comment: Minor corrections, section 5 refined, references added

### The RN/CFT Correspondence Revisited

We reconsidered the quantum gravity description of the near horizon extremal
Reissner-Nordstr{\o}m black hole in the viewpoint of the AdS$_2$/CFT$_1$
correspondence. We found that, for pure electric case, the right moving central
charge of dual 1D CFT is $6 Q^2$ which is different from the previous result $6
Q^3$ of left moving sector obtained by warped AdS$_3$/CFT$_2$ description. We
discussed the discrepancy in these two approaches and examined novel properties
of our result.Comment: revtex4, 16 pages, sign mistakes corrected, references include

### Hidden Conformal Symmetry of the Reissner-Nordstr{\o}m Black Holes

Motivated by recent progresses in the holographic descriptions of the Kerr
and Reissner-Nordstr{\o}m (RN) black holes, we explore the hidden conformal
symmetry of nonextremal uplifted 5D RN black hole by studying the near horizon
wave equation of a massless scalar field propagating in this background.
Similar to the Kerr black hole case, this hidden symmetry is broken by the
periodicity of the associated angle coordinate in the background geometry, but
the results somehow testify the dual CFT description of the nonextremal RN
black holes. The duality is further supported by matching of the entropies and
absorption cross sections calculated from both CFT and gravity sides.Comment: 14 pages, no figur

### Holographic Dual of Linear Dilaton Black Hole in Einstein-Maxwell-Dilaton-Axion Gravity

Motivated by the recently proposed Kerr/CFT correspondence, we investigate
the holographic dual of the extremal and non-extremal rotating linear dilaton
black hole in Einstein-Maxwell-Dilaton-Axion Gravity. For the case of extremal
black hole, by imposing the appropriate boundary condition at spatial infinity
of the near horizon extremal geometry, the Virasoro algebra of conserved
charges associated with the asymptotic symmetry group is obtained. It is shown
that the microscopic entropy of the dual conformal field given by Cardy formula
exactly agrees with Bekenstein-Hawking entropy of extremal black hole. Then, by
rewriting the wave equation of massless scalar field with sufficient low energy
as the SL(2, R)$_L$$\times$SL(2, R)$_R$ Casimir operator, we find the hidden
conformal symmetry of the non-extremal linear dilaton black hole, which implies
that the non-extremal rotating linear dilaton black hole is holographically
dual to a two dimensional conformal field theory with the non-zero left and
right temperatures. Furthermore, it is shown that the entropy of non-extremal
black hole can be reproduced by using Cardy formula.Comment: 15 pages, no figure, published versio

### Holographic Duals of Near-extremal Reissner-Nordstrom Black Holes

We consider the $\mathrm{AdS}_3/\mathrm{CFT}_2$ description of
Reissner-Nordstr{\o}m black holes by studying their uplifted counterparts in
five dimensions. Assuming a natural size of the extra dimension, the near
horizon geometries for the extremal limit are exactly $\mathrm{AdS}_3 \times
\mathrm{S}^2$. We compute the scattering amplitude of a scalar field, with a
mode near threshold of frequency and extra dimensional momentum, by a near
extremal uplifted black hole. The absorption cross section agrees with the two
point function of the CFT dual to the scalar field.Comment: reference added, improper statements corrected, 17 pages, no figure

### On Holographic description of the Kerr-Newman-AdS-dS black holes

In this paper, we study the holographic description of the generic
four-dimensional non-extremal Kerr-Newman-AdS-dS black holes. We find that if
focusing on the near-horizon region, for the massless scalar scattering in the
low-frequency limit, there exists hidden conformal symmetry on the solution
space. Similar to the Kerr case, this suggests that the Kerr-Newman-AdS-dS
black hole is dual to a two-dimensional CFT with central charges
$c_L=c_R=\frac{6a(r_++r_\ast)}{k}$ and temperatures
$T_L=\frac{k(r_+^2+r_\ast^2+2a^2)}{4\pi a\Xi(r_++r_\ast)},
T_R=\frac{k(r_+-r_\ast)}{4\pi a\Xi}$. The macroscopic Bekenstein-Hawking
entropy could be recovered from the microscopic counting in dual CFT via the
Cardy formula. Using the Minkowski prescription, we compute the real-time
correlators of the scalar, photon and graviton in near horizon geometry of near
extremal Kerr-AdS-dS black hole. In all these cases, the retarded Green's
function and the corresponding absorption cross section are in perfect match
with CFT prediction. We further discuss the low-frequency scattering of a
charged scalar by a Kerr-Newman-AdS-dS black hole and find the dual CFT
description.Comment: 22 pages; minor corrections, conlusion unchanged, references
added;published versio