Higher-dimensional evolving wormholes satisfying the null energy condition

TL;DR

This paper explores higher-dimensional evolving wormholes in cosmological backgrounds, identifying solutions that satisfy the null energy condition, including some in five dimensions that do so throughout their evolution.

Contribution

It introduces a class of higher-dimensional wormhole solutions with a homogeneous Ricci scalar, demonstrating the existence of NEC-satisfying solutions in specific dimensions and time intervals.

Findings

Found wormhole solutions satisfying NEC in four dimensions during certain times.

Discovered five-dimensional solutions that satisfy NEC throughout their evolution.

Showed that non-trivial topological objects like wormholes can be compatible with normal matter under certain conditions.

Abstract

In this work, we consider the possibility of expanding wormholes in higher-dimensions, which is an important ingredient of modern theories of fundamental physics. An important motivation is that non-trivial topological objects such as microscopic wormholes may have been enlarged to macroscopic sizes in an expanding inflationary cosmological background. Since the Ricci scalar is only a function of time in standard cosmological models, we use this property as a simplifying assumption. More specifically, we consider a particular class of wormhole solutions corresponding to the choice of a spatially homogeneous Ricci scalar. The possibility of obtaining solutions with normal and exotic matter is explored and we find a variety of solutions including those in four dimensions that satisfy the null energy condition (NEC) in specific time intervals. In particular, for five dimensions, we find solutions that satisfy the NEC throughout the respective evolution.