374 research outputs found
The Kerr/CFT Correspondence
Quantum gravity in the region very near the horizon of an extreme Kerr black
hole (whose angular momentum and mass are related by J=GM^2) is considered. It
is shown that consistent boundary conditions exist, for which the asymptotic
symmetry generators form one copy of the Virasoro algebra with central charge
c_L=12J / \hbar. This implies that the near-horizon quantum states can be
identified with those of (a chiral half of) a two-dimensional conformal field
theory (CFT). Moreover, in the extreme limit, the Frolov-Thorne vacuum state
reduces to a thermal density matrix with dimensionless temperature T_L=1/2\pi
and conjugate energy given by the zero mode generator, L_0, of the Virasoro
algebra. Assuming unitarity, the Cardy formula then gives a microscopic entropy
S_{micro}=2\pi J / \hbar for the CFT, which reproduces the macroscopic
Bekenstein-Hawking entropy S_{macro}=Area / 4\hbar G. The results apply to any
consistent unitary quantum theory of gravity with a Kerr solution. We
accordingly conjecture that extreme Kerr black holes are holographically dual
to a chiral two-dimensional conformal field theory with central charge c_L=12J
/ \hbar, and in particular that the near-extreme black hole GRS 1915+105 is
approximately dual to a CFT with c_L \sim 2 \times 10^{79}.Comment: 21 pages, no figure
Microscopic Entropy of the Black Ring
A surprising new seven-parameter supersymmetric black ring solution of
five-dimensional supergravity has recently been discovered. In this paper,
M-theory is used to give an exact microscopic accounting of its entropy.Comment: 5 pages; v2: References and acknowledgements adde
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