Cosmic expansion with perturbed Friedmann equations

Authors

Carl Justin Palpal-latoc ⋅ PH National Institute of Physics, University of the Philippines Diliman
Michael Francis Ian G. Vega II ⋅ PH National Institute of Physics, University of the Philippines Diliman

Abstract

A time-delayed Friedmann equation can accommodate inflationary scenarios that naturally end without violating energy conditions or invoking scalar fields. But robust data-driven constraints on the theory are yet to be established. As a step forward, we take first- and second-order Taylor expansions of the delayed Friedmann equation as phenomenological models. We use these perturbed models to obtain predictions of the Hubble expansion rate H(z) and compute the best-fit parameters. For the first-order model, we find that a delay 𝜏 = 0.51^+2.53_‒_0.40 Gyr is most consistent with the data and for the second-order model, 𝜏 = 0.25^+0.45_‒0.14 Gyr. We also find moderately strong statistical preference for the first- and second-order models over the standard ΛCDM model.

Downloads

Issue

2021: Proceedings of the 39th Samahang Pisika ng Pilipinas Physics Conference

Article ID

SPP-2021-PC-07

Section

Poster Session C (Theoretical and Mathematical Physics)

Published

2021-09-30

How to Cite

[1]

CJ Palpal-latoc and MFIG Vega, Cosmic expansion with perturbed Friedmann equations, Proceedings of the Samahang Pisika ng Pilipinas 39, SPP-2021-PC-07 (2021). URL: https://proceedings.spp-online.org/article/view/SPP-2021-PC-07.