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

Can Self-Prediction Overcome Barriers to Hepatitis B Vaccination? A Randomized Controlled Trial

Objective: Hepatitis B virus (HBV) infection remains a serious public health problem, due in part to low vaccination rates among high-risk adults, many of whom decline vaccination because of barriers such as perceived inconvenience or discomfort. This study evaluates the efficacy of a self-prediction intervention to increase HBV vaccination rates among high-risk adults. Method: Randomized controlled trial of 1,175 adults recruited from three sexually transmitted disease clinics in the United States over 28 months. Participants completed an audio-computer-assisted self-interview, which presented information about HBV infection and vaccination, and measured relevant beliefs, behaviors, and demographics. Half of participants were assigned randomly to a “self-prediction” intervention, asking them to predict their future acceptance of HBV vaccination. The main outcome measure was subsequent vaccination behavior. Other measures included perceived barriers to HBV vaccination, measured prior to the intervention. Results: There was a significant interaction between the intervention and vaccination barriers, indicating the effect of the intervention differed depending on perceived vaccination barriers. Among high-barriers patients, the intervention significantly increased vaccination acceptance. Among low-barriers patients, the intervention did not influence vaccination acceptance. Conclusions: The self-prediction intervention significantly increased vaccination acceptance among “high-barriers” patients, who typically have very low vaccination rates. This brief intervention could be a useful tool in increasing vaccine uptake among high-barriers patients

Moduli Space of Torsional Manifolds

We characterize the geometric moduli of non-Kaehler manifolds with torsion. Heterotic supersymmetric flux compactifications require that the six-dimensional internal manifold be balanced, the gauge bundle be hermitian Yang-Mills, and also the anomaly cancellation be satisfied. We perform the linearized variation of these constraints to derive the defining equations for the local moduli. We explicitly determine the metric deformations of the smooth flux solution corresponding to a torus bundle over K3.Comment: 23 pages, harvmac; v2: typos corrected, minor clarifications, reference adde

Heterotic String Compactifications on Half-flat Manifolds II

In this paper, we continue the analysis of heterotic string compactifications on half-flat mirror manifolds by including the 10-dimensional gauge fields. It is argued, that the heterotic Bianchi identity is solved by a variant of the standard embedding. Then, the resulting gauge group in four dimensions is still E6 despite the fact that the Levi-Civita connection has SO(6) holonomy. We derive the associated four-dimensional effective theories including matter field terms for such compactifications. The results are also extended to more general manifolds with SU(3) structure.Comment: 31 page

Non-supersymmetric black rings as thermally excited supertubes

We construct a seven-parameter family of supergravity solutions that describe non-supersymmetric black rings and black tubes with three charges, three dipoles and two angular momenta. The black rings have regular horizons and non-zero temperature. They are naturally interpreted as the supergravity descriptions of thermally excited configurations of supertubes, specifically of supertubes with two charges and one dipole, and of supertubes with three charges and two dipoles. In order to fully describe thermal excitations near supersymmetry of the black supertubes with three charges and three dipoles a more general family of black ring solutions is required.Comment: 35 pages. v2: ref added and minor typo correcte

A microstate for the 3-charge black ring

We start with a 2-charge D1-D5 BPS geometry that has the shape of a ring; this geometry is regular everywhere. In the dual CFT there exists a perturbation that creates one unit of excitation for left movers, and thus adds one unit of momentum P. This implies that there exists a corresponding normalizable perturbation on the near-ring D1-D5 geometry. We find this perturbation, and observe that it is smooth everywhere. We thus find an example of `hair' for the black ring carrying three charges -- D1, D5 and one unit of P. The near-ring geometry of the D1-D5 supertube can be dualized to a D6 brane carrying fluxes corresponding to the `true' charges, while the quantum of P dualizes to a D0 brane. We observe that the fluxes on the D6 brane are at the threshold between bound and unbound states of D0-D6, and our wavefunction helps us learn something about binding at this threshold.Comment: 31 pages, 3 figures; references adde

Black Rings in Taub-NUT

We construct the most generic three-charge, three-dipole-charge, BPS black-ring solutions in a Taub-NUT background. These solutions depend on seven charges and six moduli, and interpolate between a four-dimensional black hole and a five-dimensional black ring. They are also instrumental in determining the correct microscopic description of the five-dimensional BPS black rings.Comment: 16 pages, harvma

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

Classifying Supergravity Solutions

We review the substantial progress that has been made in classifying supersymmetric solutions of supergravity theories using G-structures. We also review the construction of supersymmetric black rings that were discovered using the classification of D=5 supergravity solutions.Comment: 16 pages. To appear in the Proceedings of the 37th International Symposium Ahrenshoop, ``Recent Developments in String/M-Theory and Field Theory", August 23-27 2004, Berlin-Schmoeckwitz. References adde