Cosmological evolution of a ghost scalar field

TL;DR

This paper presents an exact solution for a ghost scalar field that forms a wormhole connecting two accelerating, expanding universes, with the nature of acceleration depending on the wormhole's mass parameter.

Contribution

It introduces a novel exact non-static spherically symmetric solution involving a ghost scalar field in a cosmological context, demonstrating wormhole connections between expanding universes.

Findings

Wormhole connects two homogeneous flat universes.

Acceleration can be constant or infinite depending on mass parameter.

Solution describes a cosmological wormhole with specific scalar field properties.

Abstract

We consider a scalar field with a negative kinetic term minimally coupled to gravity. We obtain an exact non-static spherically symmetric solution which describes a wormhole in cosmological setting. The wormhole is shown to connect two homogeneous spatially flat universes expanding with acceleration. Depending on the wormhole's mass parameter $m$ the acceleration can be constant (the de Sitter case) or infinitely growing.