Closed timelike curves and geodesics of Gödel-type metrics

Abstract

It is shown explicitly that when the characteristic vector field that defines a Gödel-type metric is also a Killing vector, there always exist closed timelike or null curves in spacetimes described by such a metric. For these geometries, the geodesic curves are also shown to be characterized by a lower-dimensional Lorentz force equation for a charged point particle in the relevant Riemannian background. Moreover, two explicit examples are given for which timelike and null geodesics can never be closed. © 2006 IOP Publishing Ltd.