8 research outputs found
Supersymmetric black rings and three-charge supertubes
We present supergravity solutions for 1/8-supersymmetric black supertubes
with three charges and three dipoles. Their reduction to five dimensions yields
supersymmetric black rings with regular horizons and two independent angular
momenta. The general solution contains seven independent parameters and
provides the first example of non-uniqueness of supersymmetric black holes. In
ten dimensions, the solutions can be realized as D1-D5-P black supertubes. We
also present a worldvolume construction of a supertube that exhibits three
dipoles explicitly. This description allows an arbitrary cross-section but
captures only one of the angular momenta.Comment: 59 pages, 6 figures; v2: minor correction
How hairy can a black ring be?
It has been shown recently that there is a large class of supersymmetric
solutions of five-dimensional supergravity which generalize the supersymmetric
black ring solution of Elvang et al. This class involves arbitrary functions.
We show that most of these solutions do not have smooth event horizons, so they
do not provide examples of black objects with infinite amounts of "hair".Comment: 19 pages. v2: minor change
Spacetime in String Theory
We give a brief overview of the nature of spacetime emerging from string
theory. This is radically different from the familiar spacetime of Einstein's
relativity. At a perturbative level, the spacetime metric appears as ``coupling
constants" in a two dimensional quantum field theory. Nonperturbatively (with
certain boundary conditions), spacetime is not fundamental but must be
reconstructed from a holographic, dual theory.Comment: 20 pages; references adde