title: A class of time-machine solutions with a compact vacuum core.
abstract: We present a class of curved-spacetime vacuum solutions which develop closed timelike curves at some particular moment. We then use these vacuum solutions to construct a time-machine model. The causality violation occurs inside an empty torus, which constitutes the time-machine core. The matter field surrounding this empty torus satisfies the weak, dominant, and strong energy conditions. The model is regular, asymptotically flat, and topologically trivial. Stability remains the main open question.
authors.affiliation: Department of Physics, Technion--Israel Institute of Technology, Haifa, 32000, Israel.
authors.forename: Amos
authors.initials: A
authors.lastname: Ori