Solar system constraints on f(T) gravity

TL;DR

This paper uses solar system orbital data to place stringent constraints on f(T) gravity models, showing that deviations from General Relativity are extremely small within the solar system, which impacts future model development.

Contribution

It provides the first detailed solar system constraints on f(T) gravity, focusing on quadratic corrections and their effects on planetary perihelion shifts.

Findings

Maximum divergence of gravitational potential is 6.2 x 10^{-10}.

Constraints are much tighter than cosmological predictions.

Results inform f(T) model building to ensure consistency with solar system tests.

Abstract

We use recent observations from solar system orbital motions in order to constrain f(T) gravity. In particular, imposing a quadratic f(T) correction to the linear-in-T form, which is a good approximation for every realistic case, we extract the spherical solutions of the theory. Using these spherical solutions to describe the Sun's gravitational field, we use recently determined supplementary advances of planetary perihelia, to infer upper bounds on the allowed f(T) corrections. We find that the maximal allowed divergence of the gravitational potential in f(T) gravity from that in the teleparallel equivalent of General Relativity is of the order of 6.2 \times 10^{-10}, in the applicability region of our analysis. This is much smaller than the corresponding (significantly small too) divergence that is predicted from cosmological observations, as expected. Such a tiny allowed divergence from the linear form should be taken into account in f(T) model building.