The Lifespan of our Universe

TL;DR

This paper discusses how measurements suggesting dark energy's equation of state differs from -1 can be explained by an axion dark energy model, predicting a universe lifespan of about 33 billion years before a potential big crunch.

Contribution

It introduces an axion dark energy model that accounts for observed deviations in dark energy behavior and predicts a finite universe lifespan.

Findings

Best-fit model suggests universe lifespan of 33 billion years.

High probability of negative cosmological constant leading to a big crunch.

Model explains deviations in dark energy equation of state.

Abstract

The Dark Energy Survey (DES) and the Dark Energy Spectroscopic Instrument (DESI) measurements claim that the dark energy equation of state $w \ne -1$. This observation can be explained by the axion Dark Energy (aDE) model of an ultralight axion plus a cosmological constant $\Lambda$. Despite a relatively large degeneracy, there is a high probability that $\Lambda <0$. This negative $\Lambda$ leads the universe to end in a big crunch. Using the best-fit values of the model as a benchmark, we find the lifespan of our universe to be 33 billion years.