Wormholes supported by hybrid metric-Palatini gravity

TL;DR

This paper explores the possibility of wormholes supported by a hybrid metric-Palatini gravity theory, deriving conditions for solutions and providing specific examples of both non-asymptotically flat and asymptotically flat wormhole spacetimes.

Contribution

It introduces the first analysis of wormhole solutions within hybrid metric-Palatini gravity, including explicit examples and conditions based on null energy constraints.

Findings

Wormhole solutions can exist under null energy conditions in this theory.

Explicit non-asymptotically flat and asymptotically flat wormhole examples are provided.

Conditions for wormhole support depend on scalar field and metric function choices.

Abstract

Recently, a modified theory of gravity was presented, which consists of the superposition of the metric Einstein-Hilbert Lagrangian with an $f(\cal R)$ term constructed \`{a} la Palatini. The theory possesses extremely interesting features such as predicting the existence of a long-range scalar field, that explains the late-time cosmic acceleration and passes the local tests, even in the presence of a light scalar field. In this brief report, we consider the possibility that wormholes are supported by this hybrid metric-Palatini gravitational theory. We present here the general conditions for wormhole solutions according to the null energy conditions at the throat and find specific examples. In the first solution, we specify the redshift function, the scalar field and choose the potential that simplifies the modified Klein-Gordon equation. This solution is not asymptotically flat and needs to be matched to a vacuum solution. In the second example, by adequately specifying the metric functions and choosing the scalar field, we find an asymptotically flat spacetime.