Are black holes in an ekpyrotic phase possible?

TL;DR

This paper investigates the possibility of black hole formation during the ekpyrotic phase of the universe, concluding that spherical black holes supported by isotropic fluids cannot form in this scenario.

Contribution

It introduces a linear metric deformation approach to analyze black hole formation in the ekpyrotic phase and demonstrates the impossibility of such black holes in this context.

Findings

Black holes with spherical symmetry cannot form supported by isotropic fluids during the ekpyrotic phase.

The linear deformation approach effectively analyzes black hole viability in alternative cosmological models.

Abstract

The ekpyrotic phase (a slow contraction cosmic phase before the current expansion phase) manages to solve the main problems of the standard cosmology by means of a scalar field interpreted as a cosmic fluid in the Friedmann equation. Moreover, this phase generates a nearly scale-invariant spectrum of perturbations in agreement with the latest data. Then, the ekpyrotic mechanism is a serious possibility to the inflationary model. In this work, by using the approach of deforming metrics at linear level, we point out that it is impossible to generate a black hole with spherical symmetry supported by an isotropic fluid in this cosmological scenario.