Model independent tests of the standard cosmological model

TL;DR

This paper explores model-independent tests of the standard cosmological model using direct H(z) measurements, aiming to verify assumptions like flatness, homogeneity, and the validity of LCDM without relying on specific dark energy models.

Contribution

It introduces methods to test fundamental cosmological assumptions independently of dark energy or gravity theories, utilizing H(z) data combined with supernovae distances.

Findings

Current data is too weak for definitive conclusions.

Proposed tests can verify flatness and homogeneity independently.

Future data could significantly improve these tests.

Abstract

The dark energy problem has led to speculation that not only may LCDM be wrong, but that the FLRW models themselves may not even provide the correct family of background models. We discuss how direct measurements of H(z) can be used to formulate tests of the standard paradigm in cosmology. On their own, such measurements can be used to test for deviations from flat LCDM. When combined with supernovae distances, Hubble rate measurements provide a test of the Copernican principle and the homogeneity assumption of the standard model, which is independent of dark energy or metric based theory of gravity. A modification of this test also provides a model independent observable for flatness which decorrelates curvature determination from dark energy. We investigate these tests using Hubble rate measurements from age data, as well as from a Hubble rate inferred from recent measurements of the baryon acoustic oscillations. While the current data is too weak to say anything significant, these tests are exciting prospects for the future.