Multi-mouth traversable wormholes

We describe the construction of traversable wormholes with multiple mouths in four spacetime dimensions and discuss associated quantum entanglement. Our wormholes may be traversed between any pair of mouths. In particular, in the three-mouth case they have fundamental group F-2 (the free group on two generators). By contrast, connecting three regions A, B, C in pairs (AB, BC, and AC) using three separate wormholes would give fundamental group F-3. Our solutions are asymptotically flat up to the presence of possible magnetic fluxes or cosmic strings that extend to infinity. The construction begins with a two-mouth traversable wormhole supported by backreaction from quantum fields. Inserting a sufficiently small black hole into its throat preserves traversability between the original two mouths. This black hole is taken to be the mouth of another wormhole connecting the original throat to a new distant region of spacetime. Making the new wormhole traversable in a manner similar to the original two-mouth wormhole provides the desired causal connections. From a dual field theory point of view, when AdS asymptotics are added to our construction, multiparty entanglement may play an important role in the traversability of the resulting wormhole.

Automated summary

This article discusses the construction of traversable wormholes with multiple mouths in four spacetime dimensions and the associated quantum entanglement. The solutions allow for traversal between any pair of mouths, with specific fundamental groups in the case of multiple mouths. By inserting black holes and extending possible magnetic fluxes or cosmic strings to infinity, the construction of these wormholes is achieved. Multiparty entanglement may also play a significant role in the traversability of these wormholes when AdS asymptotics are added to the construction.