Tides and energy conditions in Einstein-Gauss-Bonnet thin-shell wormholes

TL;DR

This paper shows that thin-shell wormholes in five-dimensional Einstein-Gauss-Bonnet gravity can be sustained by ordinary matter obeying the weak energy condition while avoiding dangerous radial tides at the throat, by leveraging the non-GR branch with a positive Gauss-Bonnet coupling $\alpha$. Using geometric junction conditions appropriate for Einstein-Gauss-Bonnet theory, the authors derive shell quantities $\sigma(a)$ and $p(a)$ and demonstrate that setting $f'(a)=0$ eliminates radial tides, with $\sigma(a)\ge0$ implying traversability with ordinary matter. They derive throat and singular-surface relations under $\Lambda<0$, $Q=0$, and $\alpha>0$, and show that the required parameter regime exists (via a bound on $\sqrt{M}$) to satisfy energy conditions; to avoid ill-defined exterior regions, they propose two cut-and-paste constructions that join a central throat region to well-behaved outer spacetimes. In one construction, the total exotic matter vanishes and the far-field behavior is controlled; in the other, outer shells with normal matter satisfy the weak energy condition, at the expense of non-asymptotically flat exteriors with negative effective cosmological constant. Overall, the Gauss-Bonnet corrections enable ordinary-matter traversable wormholes in higher dimensions with manageable tidal and global properties.

Abstract

In this article we study spherical thin-shell wormholes in five-dimensional Einstein-Gauss-Bonnet gravity. We show that configurations supported by non-exotic matter, that is matter satisfying the weak energy condition, are possible at the same time that traversability problems associated with strong radial tides at the throat can be avoided when suitable values of the parameters are adopted. Our construction is performed in such a way that it also allows for the admissible behaviour of the geometry in the whole spacetime.