Model-independent Reconstruction of f(T) Gravity from Gaussian Processes

Abstract

We apply Gaussian processes and Hubble function data in f (T ) cosmology, to reconstruct for the first time the f (T ) form in a model-independent way. In particular, using H(z) datasets coming from cosmic chronometers as well as from the radial BAO method, alongside the latest released local value H0 = 73.52 ± 1.62 km/s/Mpc, we reconstruct H(z) and its derivatives, resulting eventually in a reconstructed region for f (T ), without any assumption. Although the cosmological constant lies in the central part of the reconstructed region, the obtained mean curve follows a quadratic function. Inspired by this we propose a new f (T ) parametrization, i.e. f (T ) = −2Λ + ξT 2 , with ξ the sole free parameter that quantifies the deviation from ΛCDM cosmology. Additionally, we confront three viable one-parameter f (T ) models of the literature, which respectively are the power-law, the square-root exponential, and the exponential one, with the reconstructed f (T ) region, and then we extract significantly improved constraints for their model parameters, comparing to the constraints that arise from usual observational analysis. Finally, we argue that since we are using the direct Hubble measurements and the local value for H0 in our analysis, with the above reconstruction of f (T ), the H0 tension can be efficiently alleviated.

Measurements of H0 in modified gravity theories: The role of lensed quasars in the late-time Universe

“…[41] for a review). Also, the fðTÞ theories have been shown to be a strong and viable modified gravity candidate alternative to GR [42][43][44][45][46][47][48][49][50][51][52].…”

Non-parametric reconstruction of the cosmological jerk parameter

“…For a detailed overview one can refer to the Gaussian Process website. 1 In cosmology, GP has attracted a wide application in reconstructing or testing models without an a priori fiducial model [9,24,[37][38][39][40][41][42][43][44][45][46][47]. For a pedagogical introduction to GP, one can refer to Seikel et al [37].…”

Analysis of the H0 tension problem in the Universe with viscous dark fluid

“…The red dots represent the known observational HðzÞ data, and it is the same as in Ref. [42]. The left-hand side represents the comparison for the model given by Eq.…”

“…It has been shown that some of the interacting dynamical models existing on the market can be used to solve the issue. On the other hand, a modification of General Relativity can also propose solutions [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] (to mention some references). In this paper we discuss another approach to address this issue.…”