Squashed Kerr-Godel Black Holes - Kaluza-Klein Black Holes with Rotations of Black Hole and Universe -

TL;DR

This paper introduces a new class of five-dimensional rotating Kaluza-Klein black hole solutions derived from Kerr-Godel black holes, featuring unique properties like dual ergoregions and rotations, with no closed timelike curves outside the horizons.

Contribution

The authors construct novel squashed Kerr-Godel black hole solutions in five-dimensional Einstein-Maxwell theory with Chern-Simon term, highlighting their unique rotational and geometric features.

Findings

Solutions have no closed timelike curves outside horizons.

Existence of two disconnected ergoregions with independent rotations.

Asymptotic structure approaches a twisted S^1 bundle over Minkowski space.

Abstract

Applying squashing transformation to Kerr-Godel black hole solutions, we present a new type of a rotating Kaluza-Klein black hole solution to the five-dimensional Einstein-Maxwell theory with a Chern-Simon term. The new solutions generated via the squashing transformation have no closed timelike curve everywhere outside the black hole horizons. At the infinity, the metric asymptotically approaches a twisted S^1 bundle over a four-dimensional Minkowski space-time. One of the remarkable features is that the solution has two independent rotation parameters along an extra dimension associated with the black hole's rotation and the Godel's rotation. The space-time also admits the existence of two disconnected ergoregions, an inner ergoregion and an outer ergoregion. These two ergoregions can rotate in the opposite direction as well as in the same direction.