Windowing Artifacts Likely Account for Recent Claimed Detection of Oscillating Cosmic Scale Factor

TL;DR

This study shows that claimed detections of oscillations in the universe's expansion are likely artifacts caused by data analysis methods and data structure, not actual cosmic phenomena.

Contribution

The paper demonstrates that analysis artifacts can mimic oscillating signals in cosmological data, challenging previous claims of oscillating cosmic scale factors.

Findings

Oscillations in data are likely artifacts, not real cosmic signals.

Analysis method and data structure induce false oscillatory signals.

Simulated data reproduces the claimed signals without real oscillations.

Abstract

Using the Pantheon data set of Type Ia supernovae, a recent publication (R20 in this work) reports a $~2\sigma$ detection of oscillations in the expansion history of the universe. Applying the R20 methodology to simulated Pantheon data, we determine that these oscillations likely arise from analysis artifacts. The uneven spacing of Type Ia supernovae in redshift space and the complicated analysis method of R20 impose a structured throughput function. When analyzed with the R20 prescription, about $11\%$ of artificial $\Lambda$CDM data sets produce a stronger oscillatory signal than the actual Pantheon data. The study conducted by R20 is a wholly worthwhile endeavor. However, we believe that the detected oscillations are not due to an oscillating cosmic scale factor and are instead artifacts of the data processing. Our results underscore the importance of understanding the false `signals' that can be introduced by complicated data analyses.