Enhanced Big Rip without Conventional Dark Energy

TL;DR

This paper explores a modified cosmological model derived from an extended theory of gravity with a time-dependent length scale, predicting a finite-time Big Rip without traditional dark energy, consistent with supernova data.

Contribution

It introduces a new cosmological model based on a modified Friedmann equation with a dynamic length scale, avoiding conventional dark energy.

Findings

Predicts a finite-time Big Rip with an essential singularity.

Supernova data constrains the Rip to occur longer than the current universe age.

Models do not rely on traditional dark energy with simple pressure-energy relations.

Abstract

A modified Friedmann equation which arises in an extension of general relativity which accommodates a time-dependent fundamental length $L(t)$ leads to cosmological models where the scale factor diverges with an essential singularity at a finite future time. Such models have no dark energy in the conventional sense of energy possessing a truly simple pressure-energy relationship. Data on supernovae restrict the time from the present until the Rip to be generically longer than the current age of the Universe.