Wormhole geometries in modified gravity

TL;DR

This paper reviews recent developments in wormhole geometries within modified gravity theories, highlighting how higher order curvature terms can sustain wormholes without exotic matter, unlike in general relativity.

Contribution

It summarizes recent research showing that modified gravity allows for wormholes supported by normal matter, reducing the need for exotic matter in these geometries.

Findings

Higher order curvature terms act as a gravitational fluid.

Normal matter can satisfy the null energy condition.

Modified gravity enables wormholes without exotic matter.

Abstract

A fundamental ingredient in wormhole physics is the presence of exotic matter, which involves the violation of the null energy condition. Although a plethora of wormhole solutions have been explored in the literature, it is useful to find geometries that minimize the usage of exotic matter. In the context of modified gravity, it has also been shown that the normal matter can be imposed to satisfy the null energy condition, and it is the higher order curvature terms, interpreted as a gravitational fluid, that sustain these non-standard wormhole geometries, fundamentally different from their counterparts in general relativity. In this paper, we review recent work in wormhole physics in the context of modified theories of gravity.