We discuss supersymmetric black holes embedded in a Gödel-type universe with cosmological constant in five dimensions. The spacetime is a fibration over a four-dimensional Kähler base manifold, and generically has closed timelike curves. Asymptotically the space approaches a deformation of AdS5, which suggests that the appearance of closed timelike curves should have an interpretation in some d...

We argue that a technique called analytic perturbation theory leads to a well-defined method for analytically continuing the running coupling constant from the spacelike to the timelike region, which allows us to give a selfconsistent definition of the running coupling constant for timelike momentum. The corresponding β-function is proportional to the spectral density, which confirms a hypothes...

We present various supergravity black holes of different dimensions with some U(1) charges set equal in a simple, common form. Black hole solutions of seven dimensional U(1) gauged supergravity with three independent angular momenta and two equal U(1) charges are obtained. We investigate the thermodynamics and the BPS limit of this solution, and find that there are rotating supersymmetric black...

We study (3+ 1)+D dimensional spacetime, where D extra dimensions are timelike. Compactification of the D timelike dimensions leads to tachyonic Kaluza-Klein gravitons. We calculate the gravitational self-energies of massive spherical bodies due to the tachyonic exchange, discuss their stability, and find that the gravitational force is screened in a certain number of the extra dimensions. We a...

In this paper we prove that for any spacelike hypersurface containing an untrapped barrier in a stationary spacetime satisfying the null energy condition, any marginally outer trapped surface cannot lie in the exterior region where the stationary Killing vector is timelike. In the static case we prove that any marginally outer trapped surface cannot penetrate into the exterior region where the ...

The existence and stability under linear perturbations of closed timelike geodesics (CTG) in Bonnor-Ward spacetime is studied in some detail. Regions where the CTG exist and are linearly stable are exhibited. In 1949 Gödel found a solution to the Einstein field equation with nonzero cosmological constant that admits closed timelike curves (CTC) [1]. It could be argued that the Gödel solution is...