Probing the time dependence of dark energy

TL;DR

This paper introduces a new method to test whether dark energy's properties change over time, applying it to recent supernova and baryon acoustic oscillation data, revealing possible deviations from the standard model.

Contribution

It proposes a novel approach for detecting time dependence in dark energy's equation of state using observational data.

Findings

Possible departure from ΛCDM at intermediate redshifts.

Non-evolving dark energy cannot be definitively ruled out.

Method shows promise for future data analysis.

Abstract

A new method to investigate a possible time-dependence of the dark energy equation of state $w$ is proposed. We apply this methodology to two of the most recent data sets of type Ia supernova (Union2 and SDSS) and the baryon acoustic oscillation peak at $z = 0.35$. For some combinations of these data, we show that there is a clear departure from the standard $\Lambda$CDM model at intermediary redshifts, although a non-evolving dark energy component ($dw/dz = 0$) cannot be ruled out by these data. The approach developed here may be useful to probe a possible evolving dark energy component when applied to upcoming observational data.