General (Anti-)de Sitter Black Holes in Five Dimensions

We find a general class of rotating charged black hole solutions to N=2, D=5 gauged supergravity coupled to vector supermultiplets. The supersymmetry properties of these solutions are studied, and their mass and angular momenta are obtained. We also compute the stress tensor of the dual D=4, N=4 super Yang-Mills theory in the limit of strong `t Hooft coupling. It is shown that closed timelike curves occur outside the horizon, indicating loss of unitarity in the dual CFT. For imaginary coupling constant of the gravitini to the gauge fields, one can obtain multi-centered rotating charged de Sitter black holes. Some physical properties of these solutions are also discussed.Comment: 22 pages, LaTeX, some explanations concerning the appearance of closed timelike curves outside the horizon added in section 5.1, updated references, published versio

Theory of Coherent cc-Axis Josephson Tunneling between Layered Superconductors

We calculate exactly the Josephson current for $c$-axis coherent tunneling between two layered superconductors, each with internal coherent tight-binding intra- and interlayer quasiparticle dispersions. Our results also apply when one or both of the superconductors is a bulk material, and include the usually neglected effects of surface states. For weak tunneling, our results reduce to our previous results derived using the tunneling Hamiltonian. Our results are also correct for strong tunneling. However, the $c$-axis tunneling results of Tanaka and Kashiwaya are shown to be incorrect in any limit. In addition, we consider the $c$-axis coherent critical current between two identical layered superconductors twisted an angle $\phi_0$ about the $c$-axis with respect to each other. Regardless of the order parameter symmetry, our coherent tunneling results using a tight-binding intralayer quasiparticle dispersion are inconsistent with the recent $c$-axis twist bicrystal Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ twist junction experiments of Li {\it et al.}Comment: 11 pages, 13 figures, submitted to Physical Review

Causality Violation and Naked Time Machines in AdS_5

We study supersymmetric charged rotating black holes in AdS$_5$, and show that closed timelike curves occur outside the event horizon. Also upon lifting to rotating D3 brane solutions of type IIB supergravity in ten dimensions, closed timelike curves are still present. We believe that these causal anomalies correspond to loss of unitarity in the dual ${\cal N}=4$, D=4 super Yang-Mills theory, i.e. the chronology protection conjecture in the AdS bulk is related to unitarity bounds in the boundary CFT. We show that no charged or uncharged geodesic can penetrate the horizon, so that the exterior region is geodesically complete. These results still hold true in the quantum case, i.~e.~the total absorption cross section for Klein-Gordon scalars propagating in the black hole background is zero. This suggests that the effective temperature is zero instead of assuming the naively found imaginary value.Comment: 22 pages, Latex, uses JHEP.cls, 1 figure. v3: comments on unitarity in CFT and 2 references added. v4: changes in final remarks, final version to appear in JHE

First Law, Counterterms and Kerr-AdS_5 Black Holes

We apply the counterterm subtraction technique to calculate the action and other quantities for the Kerr--AdS black hole in five dimensions using two boundary metrics; the Einstein universe and rotating Einstein universe with arbitrary angular velocity. In both cases, the resulting thermodynamic quantities satisfy the first law of thermodynamics. We point out that the reason for the violation of the first law in previous calculations is that the rotating Einstein universe, used as a boundary metric, was rotating with an angular velocity that depends on the black hole rotation parameter. Using a new coordinate system with a boundary metric that has an arbitrary angular velocity, one can show that the resulting physical quantities satisfy the first law.Comment: 19 pages, 1 figur

Strong coupling expansion and Seiberg-Witten-Whitham equations

We study the Seiberg-Witten-Whitham equations in the strong coupling regime of the N=2 super Yang-Mills theory in the vicinity of the maximal singularities. In the case of SU(2) the Seiberg-Witten-Whitham equations fix completely the strong coupling expansion. For higher rank SU(N) they provide a set of non-trivial constraints on the form of this expansion. As an example, we study the off-diagonal couplings at the maximal point for which we propose an ansatz that fulfills all the equations.Comment: 10 pages, LaTeX, no figures; v2: The expression for the off-diagonal couplings has been corrected and numerical checks have been extended. One reference adde

Skyrmion and Skyrme-Black holes in de Sitter spacetime

Numerical arguments are presented for the existence of regular and black hole solutions of the Einstein-Skyrme equations with a positive cosmological constant. These classical configurations approach asymptotically the de Sitter spacetime. The main properties of the solutions and the differences with respect to the asymptotically flat ones are discussed. It particular our results suggest that, for a positive cosmological constant, the mass evaluated as timelike infinity in infinite. Special emphasis is set to De Sitter black holes Skyrmions which display two horizons.Comment: 11 pages, 4 figure

Time Correlation Functions of Three Classical Heisenberg Spins on an Isosceles Triangle and on a Chain: Strong Effects of Broken Symmetry

At arbitrary temperature $T$, we solve for the dynamics of single molecule magnets composed of three classical Heisenberg spins either on a chain with two equal exchange constants $J_1$, or on an isosceles triangle with a third, different exchange constant $J_2$. As T\rightrarrow\infty, the Fourier transforms and long-time asymptotic behaviors of the two-spin time correlation functions are evaluated exactly. The lack of translational symmetry on a chain or an isosceles triangle yields time correlation functions that differ strikingly from those on an equilateral trinagle with $J_1=J_2$. At low $T$, the Fourier transforms of the two autocorrelation functions with $J_1\ne J_2$ show one and four modes, respectively. For a semi-infinite $J_2/J_1$ range, one mode is a central peak. At the origin of this range, this mode has a novel scaling form.Comment: 9 pages, 14 figures, accepted for publication in Phys. Rev.