17 research outputs found
Near Extremal Kerr Entropy from AdS_2 Quantum Gravity
We analyze the asymptotic symmetries of near extremal Kerr black holes in
four dimensions using the AdS_2/CFT_1 correspondence. We find a Virasoro
algebra with central charge c_R=12J that is independent from the Virasoro
algebra (with the same central charge) that acts on the degenerate ground
state. The energy of the excitations is computed as well, and we can use
Cardy's formula to determine the near extremal entropy. Our result is
consistent with the Bekenstein-Hawking area law for near extremal Kerr black
holes.Comment: 28 pages. v2: references added, typos correcte
On the Stress Tensor of Kerr/CFT
The recently-conjectured Kerr/CFT correspondence posits a field theory dual
to dynamics in the near-horizon region of an extreme Kerr black hole with
certain boundary conditions. We construct a boundary stress tensor for this
theory via covariant phase space techniques. The structure of the stress tensor
indicates that any dual theory is a discrete light cone quantum theory, in
agreement with recent arguments by Balasubramanian et al. The key technical
step in our construction is the addition of an appropriate counter-term to the
symplectic structure, which is necessary to make the theory fully covariant and
to resolve a subtle problem involving the integrability of charges.Comment: 19 page
No Dynamics in the Extremal Kerr Throat
Motivated by the Kerr/CFT conjecture, we explore solutions of vacuum general
relativity whose asymptotic behavior agrees with that of the extremal Kerr
throat, sometimes called the Near-Horizon Extreme Kerr (NHEK) geometry. We
argue that all such solutions are diffeomorphic to the NHEK geometry itself.
The logic proceeds in two steps. We first argue that certain charges must
vanish at all times for any solution with NHEK asymptotics. We then analyze
these charges in detail for linearized solutions. Though one can choose the
relevant charges to vanish at any initial time, these charges are not
conserved. As a result, requiring the charges to vanish at all times is a much
stronger condition. We argue that all solutions satisfying this condition are
diffeomorphic to the NHEK metric.Comment: 42 pages, 3 figures. v3: minor clarifications and correction
A uniqueness theorem for degenerate Kerr-Newman black holes
We show that the domains of dependence of stationary, -regular,
analytic, electrovacuum space-times with a connected, non-empty, rotating,
degenerate event horizon arise from Kerr-Newman space-times
A Note on Conserved Charges of Asymptotically Flat and Anti-de Sitter Spaces in Arbitrary Dimensions
The calculation of conserved charges of black holes is a rich problem, for
which many methods are known. Until recently, there was some controversy on the
proper definition of conserved charges in asymptotically anti-de Sitter (AdS)
spaces in arbitrary dimensions. This paper provides a systematic and explicit
Hamiltonian derivation of the energy and the angular momenta of both
asymptotically flat and asymptotically AdS spacetimes in any dimension D bigger
or equal to 4. This requires as a first step a precise determination of the
asymptotic conditions of the metric and of its conjugate momentum. These
conditions happen to be achieved in ellipsoidal coordinates adapted to the
rotating solutions.The asymptotic symmetry algebra is found to be isomorphic
either to the Poincare algebra or to the so(D-1, 2) algebra, as expected. In
the asymptotically flat case, the boundary conditions involve a generalization
of the parity conditions, introduced by Regge and Teitelboim, which are
necessary to make the angular momenta finite. The charges are explicitly
computed for Kerr and Kerr-AdS black holes for arbitrary D and they are shown
to be in agreement with thermodynamical arguments.Comment: 27 pages; v2 : references added, minor corrections; v3 : replaced to
match published version forthcoming in General Relativity and Gravitatio
Heavy quarks in the presence of higher derivative corrections from AdS/CFT
We use the gauge-string duality to study heavy quarks in the presence of
higher derivative corrections. These corrections correspond to the finite
coupling corrections on the properties of heavy quarks in a hot plasma. In
particular, we study the effects of these corrections on the energy loss and
the dissociation length of a quark-antiquark pair. We show that the calculated
energy loss of heavy quarks through the plasma increases. We also find in
general that the dissociation length becomes shorter with the increase of
coupling parameters of higher curvature terms.Comment: 22pages, 8 figures, Revised versio
An Infinite Class of Extremal Horizons in Higher Dimensions
We present a new class of near-horizon geometries which solve Einstein's
vacuum equations, including a negative cosmological constant, in all even
dimensions greater than four. Spatial sections of the horizon are inhomogeneous
S^2-bundles over any compact Kaehler-Einstein manifold. For a given base, the
solutions are parameterised by one continuous parameter (the angular momentum)
and an integer which determines the topology of the horizon. In six dimensions
the horizon topology is either S^2 x S^2 or CP^2 # -CP^2. In higher dimensions
the S^2-bundles are always non-trivial, and for a fixed base, give an infinite
number of distinct horizon topologies. Furthermore, depending on the choice of
base we can get examples of near-horizon geometries with a single rotational
symmetry (the minimal dimension for this is eight). All of our horizon
geometries are consistent with all known topology and symmetry constraints for
the horizons of asymptotically flat or globally Anti de Sitter extremal black
holes.Comment: 42 pages, latex. v2: corrected section 6.1, two references added. v3:
modified angular momentum and corrected area comparison, version to be
published in Commun. Math. Phy