English

Machine Learning and cosmographic reconstructions of quintessence and the Swampland conjectures

Cosmology and Nongalactic Astrophysics 2021-03-31 v2 General Relativity and Quantum Cosmology High Energy Physics - Phenomenology

Abstract

We present model independent reconstructions of quintessence and the Swampland conjectures (SC) using both Machine Learning (ML) and cosmography. In particular, we demonstrate how the synergies between theoretical analyses and ML can provide key insights on the nature of dark energy and modified gravity. Using the Hubble parameter H(z)H(z) data from the cosmic chronometers we find that the ML and cosmography reconstructions of the SC are compatible with observations at low redshifts. Finally, including the growth rate data fσ8(z)f\sigma_8(z) we perform a model independent test of modified gravity cosmologies through two phase diagrams, namely Hfσ8H-f\sigma_8 and ηfσ8\eta-f\sigma_8, where the anisotropic stress parameter η\eta is obtained via the EgE_g statistics, which is related to gravitational lensing data. While the first diagram is consistent within the errors with the Λ\LambdaCDM model, the second one has a 2σ\sim 2\sigma deviation of the anisotropic stress from unity at z0.3z\sim 0.3 and a 4σ\sim 4\sigma deviation at z0.9z\sim 0.9, thus pointing toward mild deviations from General Relativity, which could be further tested with upcoming large-scale structure surveys.

Keywords

Cite

@article{arxiv.2012.12202,
  title  = {Machine Learning and cosmographic reconstructions of quintessence and the Swampland conjectures},
  author = {Rubén Arjona and Savvas Nesseris},
  journal= {arXiv preprint arXiv:2012.12202},
  year   = {2021}
}

Comments

13 pages, 6 figures, 4 tables. Changes match published version