Observational constraints on f(T) gravity from varying fundamental constants

Abstract

We use observations related to the variation of fundamental constants, in order to impose constraints on the viable and most used f(T) gravity models. In particular, for the fine-structure constant we use direct measurements obtained by different spectrographic methods, while for the effective Newton constant we use a model-dependent reconstruction, using direct observational Hubble parameter data, in order to investigate its temporal evolution. We consider two f(T) models and we quantify their deviation from Lambda CDM cosmology through a sole parameter. Our analysis reveals that this parameter can be slightly different from its Lambda CDM value, however, the best-fit value is very close to the Lambda CDM one. Hence, f(T) gravity is consistent with observations, nevertheless, as every modified gravity, it may exhibit only small deviations from Lambda CDM cosmology, a feature that must be taken into account in any f(T) model-building.