Constraining teleparallel gravity through Gaussian processes

Abstract

We apply Gaussian processes (GP) in order to impose constraints on teleparallel gravity and its f(T ) extensions. We use available H(z) observations from (i) cosmic chronometers data (CC); (ii) Supernova type Ia (SN) data from the compressed pantheon release together with the CANDELS and CLASH multi-cycle treasury programs; and (iii) baryonic acoustic oscillation (BAO) datasets from the sloan digital sky survey. For the involved covariance functions, we consider four widely used choices, namely the square exponential, Cauchy, Mat´ern and rational quadratic kernels, which are consistent with one another within 1σ confidence levels. Specifically, we use the GP approach to reconstruct a model-independent determination of the Hubble constant H0, for each of these kernels and dataset combinations. These analyses are complemented with three recently announced literature values of H0, namely (i) Riess HR 0 = 74.22 ± 1.82 km s−1 Mpc−1; (ii) H0LiCOW collaboration HHW 0 = 73.3+1.7 −1.8 km s−1 Mpc−1; and (iii) Carnegie–Chicago Hubble programme HTRGB 0 = 69.8 ± 1.9 km s−1 Mpc−1. Additionally, we investigate the transition redshift between the decelerating and accelerating cosmological phases through the GP reconstructed deceleration parameter. Furthermore, we reconstruct the model-independent evolution of the dark energy equation of state, and finally reconstruct the allowed f(T ) functions. As a result, the ΛCDM model lies inside the allowed region at 1σ in all the examined kernels and datasets, however a negative slope for f(T) versus T is slightly favoured.