Do universes with parallel cosmic strings or twodimensional wormholes have closed timelike curves?
Abstract
Regions of empty spacetime with one translation symmetry and no gravitational waves can be examined with the equations of 2+1 gravity. Such regions are locally Minkowskian but may include parallel cosmic strings or wormholes that extend to infinity in the third space dimension. The time evolution problem is set in the framework of a recent constrained Hamiltonian formulation for 2+1 gravity. A wormhole developes closed timelike curves in a finite amount of time for roughly half of all possible initial conditions. A pair of cosmic strings with relative angular momentum, unlike a spinning string, does not have closed timelike curves.
 Publication:

General Relativity and Gravitation
 Pub Date:
 February 1991
 DOI:
 10.1007/BF00772618
 Bibcode:
 1991GReGr..23..219W