410 research outputs found
Spin-Orbit Interaction from Matrix Theory
We study the leading order spin dependence of graviton scattering in eleven
dimensions, and show that the results obtained from supergravity and from
Matrix Theory precisely agree.Comment: 9 pages, LaTex. Some typos and a few formulas on p. 7 correcte
A Stress Tensor for Anti-de Sitter Gravity
We propose a procedure for computing the boundary stress tensor associated
with a gravitating system in asymptotically anti-de Sitter space. Our
definition is free of ambiguities encountered by previous attempts, and
correctly reproduces the masses and angular momenta of various spacetimes. Via
the AdS/CFT correspondence, our classical result is interpretable as the
expectation value of the stress tensor in a quantum conformal field theory. We
demonstrate that the conformal anomalies in two and four dimensions are
recovered. The two dimensional stress tensor transforms with a Schwarzian
derivative and the expected central charge. We also find a nonzero ground state
energy for global AdS_5, and show that it exactly matches the Casimir energy of
the dual N=4 super Yang-Mills theory on S^3 x R.Comment: 19 pages. added footnote, referenc
Attractors and Black Rings
The attractor mechanism is usually thought of as the fixing of the near
horizon moduli of a BPS black hole in terms of conserved charges measured at
infinity. Recent progress in understanding BPS solutions in five dimensions
indicates that this is an incomplete story. Moduli can instead be fixed in
terms of dipole charges, and their corresponding values can be found by
extremizing a certain attractor function built out of these charges. BPS black
rings provide an example of this phenomenon. We give a general derivation of
the attractor mechanism in five dimensions based on the recently developed
classification of BPS solutions. This analysis shows when it is the dipole
charges versus the conserved charges that fix the moduli. It also yields
explicit expressions for the fixed moduli.Comment: 18 pages, Harvma
Effect of Self-Interaction on Charged Black Hole Radiance
We extend our previous analysis of the modification of the spectrum of black
hole radiance due to the simplest and probably most quantitatively important
back-reaction effect, that is self-gravitational interaction, to the case of
charged holes. As anticipated, the corrections are small for low-energy
radiation when the hole is well away from extremality, butbecome qualitatively
important near extremality. A notable result is that radiation which could
leave the hole with mass and charge characteristic of a naked singularity,
predicted in the usual approximation of fixed space-time geometry, is here
suppressed. We discuss the nature of our approximations, and show how they work
in a simpler electromagnetic analogue problem.Comment: 13 pages in Latex, no figure
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