Gravitational Wormholes

TL;DR

This paper investigates the possibility of constructing wormholes in higher-curvature gravity theories without exotic matter, specifically using Einsteinian Cubic Gravity, and finds evidence for asymptotically AdS wormhole solutions.

Contribution

It demonstrates that higher-curvature gravity theories can support wormholes without exotic matter, expanding the scope of viable wormhole models beyond general relativity.

Findings

Existence of asymptotically AdS wormhole solutions in Einsteinian Cubic Gravity.

Strong curvature effects enable the formation of wormhole throats.

Wormholes can be constructed without matter violating energy conditions.

Abstract

Spacetime wormholes are evidently an essential component of the construction of a time machine. Within the context of general relativity, such objects require, for their formation, exotic matter -- matter that violates at least one of the standard energy conditions. Here, we explore the possibility that higher-curvature gravity theories might permit the construction of a wormhole without any matter at all. In particular, we consider the simplest form of a generalized quasi topological theory in four spacetime dimensions, known as Einsteinian Cubic Gravity. This theory has a number of promising features that make it an interesting phenomenological competitor to general relativity, including having non-hairy generalizations of the Schwarzschild black hole and linearized equations of second order around maximally symmetric backgrounds. By matching series solutions near the horizon and at large distances, we find evidence that strong asymptotically AdS wormhole solutions can be constructed, with strong curvature effects ensuring that the wormhole throat can exist.