Interpreting the conformal cousin of the Husain-Martinez-Nunez solution

TL;DR

This paper studies a conformally transformed inhomogeneous cosmological solution in Brans-Dicke theory, revealing diverse spacetime structures like wormholes, naked singularities, and black hole horizons, and discusses their physical interpretations.

Contribution

It introduces and analyzes a new 2-parameter inhomogeneous cosmology derived from the HMN solution, exploring its physical properties and differences from conformal copies.

Findings

The solution can describe wormholes, naked singularities, or black hole horizons.

Apparent horizons can appear and disappear in pairs.

Conformal transformations do not always preserve the original spacetime features.

Abstract

A 2-parameter inhomogeneous cosmology in Brans-Dicke theory, obtained by conformally transforming the Husain-Martinez-Nunez (HMN) scalar field solution of the Einstein equations is studied and interpreted physically. According to the values of the parameters it describes a wormhole, a naked singularity, or else a spacetime containing apparent black hole horizons which appear/disappear in pairs (as well as a cosmological horizon) as in the original HMN metric. The reasons why there isn't a one-to-one correspondence between conformal copies of this metric are discussed.