Does a wormhole survive a cosmological bounce?

TL;DR

This paper examines whether dynamical wormholes can persist through a cosmological bounce, analyzing known solutions and their causal structures to determine their survival and potential astrophysical implications.

Contribution

It demonstrates that certain known dynamical wormhole solutions can exist throughout a bouncing universe without topology change.

Findings

Dynamical wormholes exist on both sides of the bounce and at the bounce itself.

No topology change occurs in the analyzed solutions within the bouncing cosmological model.

The causal structure and matter content of these wormholes are thoroughly characterized.

Abstract

We investigate whether a dynamical wormhole could survive in a universe that undergoes a cosmological bounce. First, the conditions under which a wormhole could persist from a contracting to an expanding phase of the cosmos are presented. Then, the only two known cosmological solutions of Einstein's equations representing wormholes are analyzed, and it is shown that both dynamical wormholes exist for all cosmic times on both sides of a bouncing universe and at the bounce itself. We also provide a detailed analysis of the causal structure of such spacetimes and the matter content of the wormhole. Finally, some possible astrophysical manifestations of surviving wormholes in a bouncing universe are mentioned. Our results show that, at least for the Kim and P\'erez-Raia Neto solutions, there is no topology change in the chosen cosmological model with a bounce.