Towards a future singularity?

TL;DR

This paper explores the potential for future cosmological singularities within scalar-tensor gravity models, emphasizing the importance of frame-independent analysis of curvature singularities even with dark energy having negative pressure.

Contribution

It introduces the significance of frame-dependent geodesics in scalar-tensor models and advocates for a frame-independent approach to understanding singularities in cosmology.

Findings

Different test particles may follow different geodesics in scalar-tensor models.

Frame-independent regularization is crucial for analyzing curvature singularities.

Potential for future singularities exists even with dark energy pressure w ≥ -1.

Abstract

We discuss whether the future extrapolation of the present cosmological state may lead to a singularity even in case of "conventional" (negative) pressure of the dark energy field, namely $w=p/\rho \geq -1$. The discussion is based on an often neglected aspect of scalar-tensor models of gravity: the fact that different test particles may follow the geodesics of different metric frames, and the need for a frame-independent regularization of curvature singularities.