Some unusual wormholes in general relativity

In this short review, we present some recently obtained traversable wormhole models in the framework of general relativity (GR) in four and six dimensions that somehow widen our common ideas on wormhole existence and properties. These are, first, rotating cylindrical wormholes, asymptotically flat in the radial direction and existing without exotic matter. The topological censorship theorems are not violated due to lack of asymptotic flatness in all spatial directions. Second, these are cosmological wormholes constructed on the basis of the Lemaitre-Tolman-Bondi solution. They connect two copies of a closed Friedmann world filled with dust, or two otherwise distant parts of the same Friedmann world. Third, these are wormholes obtained in six-dimensional GR, whose one entrance is located in 'our' asymptotically flat world with very small extra dimensions while the other 'end' belongs to a universe with large extra dimensions and therefore different physical properties. The possible observable features of such wormholes are briefly discussed.This article is part of the theme issue 'The future of mathematical cosmology, Volume 1'.

Automated summary

In this review, the authors present recently obtained traversable wormhole models in the framework of general relativity in four and six dimensions, expanding our understanding of wormhole existence and properties. These models include rotating cylindrical wormholes, cosmological wormholes based on the Lemaitre-Tolman-Bondi solution, and wormholes obtained in six-dimensional GR.