A Topological Drive for Spacetime Travel

We present a toymetric of spacetime travel from topological change. A bubble-like baby universe is detached and re-attached fromour universe. Dependingon where the bubble is re-attached, matter may travel superluminally or backwards-in-time through the bubble. Quasiregular singularities are formed at the detachment and re-attachment spacetime points. The spacetime is traversable and not covered by any horizons. Exotic matters violating energy conditions are required to realize such spacetimes.