A wormhole with two black holes

Abstract

We report on a new three-parameter stationary solution of the four-dimensional vacuum Einstein equations, which describes a Lorentzian wormhole harboring two antipodal co-rotating black holes. These are hung from one of the two spacelike infinities by two semi-infinite cosmic strings with positive or negative tension. We evaluate the Komar masses and angular momenta of the two black holes, and check that these obey the usual Smarr relation, as well as the generalized first law for a system of collinear black holes and cosmic strings. While free from Misner strings, this spacetime allows closed timelike curves within a bounded volume. The metric also admits a naked ring singularity for almost all values of the parameters.