New Cosmological Solutions in Massive Gravity

TL;DR

This paper introduces new cosmological solutions in massive gravity that include flat, open, and closed geometries, demonstrating self-acceleration and stability, with potential applications in both cosmology and gravitational collapse studies.

Contribution

It provides explicit new solutions with various spatial geometries in massive gravity, expanding beyond previous limitations to include closed and flat models.

Findings

Solutions include flat, open, and closed geometries.

Solutions exhibit self-acceleration without ghost instabilities.

Can model inhomogeneous dust collapse with LTB metric.

Abstract

We find new, simple cosmological solutions with flat, open, and closed spatial geometries, contrary to the previous wisdom that only the open model is allowed. The metric and the St\"{u}ckelberg fields are given explicitly, showing nontrivial configurations of the St\"{u}ckelberg in the usual Friedmann-Lema\^{i}tre-Robertson-Walker coordinates. The solutions exhibit self-acceleration, while being free from ghost instabilities. Our solutions can accommodate inhomogeneous dust collapse represented by the Lema\^{i}tre-Tolman-Bondi metric as well. Thus, our results can be used not only to describe homogeneous and isotropic cosmology but also to study gravitational collapse in massive gravity.