J. P. Gregory | Searcharxiv

arXiv2003

Rotating Black Holes in a Goedel Universe

We construct a five--dimensional, asymptotically Goedel, three--charge black hole via dimensional reduction of an asymptotically plane wave, rotating D1-D5-brane solution of type IIB supergravity. This latter is itself constructed via the solution generating procedure of Garfinkle and Vachaspati, applied to the standard rotating D1-D5-brane solution. Taking all charges to be equal gives a "BMPV Goedel black hole", which is closely related to that recently found by Herdeiro. We emphasise, however, the importance of our ten--dimensional microscopic description in terms of branes. We discuss various properties of the asymptotically Goedel black hole, including the physical bound on the rotation of the hole, the existence of closed timelike curves, and possible holographic protection of chronology.

hep-th↗

arXiv2002

String theory and the Classical Stability of Plane Waves

The presence of fields with negative mass-squared typically leads to some form of instability in standard field theories. The observation that, at least in the light-cone gauge, strings propagating in plane wave spacetimes can have worldsheet scalars with such tachyon-like masses suggests that the supergravity background may itself be unstable. To address this issue, we perform a perturbative analysis around the type IIB vacuum plane wave, the solution which most obviously generates worldsheet scalars with negative mass-squared. We argue that this background is perturbatively stable.

hep-th↗