Gravitation, experiment and cosmology

TL;DR

This paper surveys how general relativity and its plausible deviations fare against a broad suite of experiments and observations, from the solar system to binary pulsars and cosmology. It emphasizes a field-theoretic framework, contrasting phenomenological tests with theory-space approaches, and shows that GR remains consistent with current data while tightly constraining extra long-range fields, especially scalar (dilaton/moduli) couplings. The strongest current validations come from weak-field post-Newtonian tests (γ and β) and strong-field binary pulsar observations; however, strong-field parameters remain a frontier for discovering potential deviations. Cosmological considerations, particularly moduli dynamics and their coupling to gravity, can both guide and complicate low-energy gravity, with implications for dark matter, inflation, and the evolution of fundamental constants.

Abstract

The confrontation between general relativity (and its theoretically most plausible deviations) and experimental or observational results is summarized. Some discussion is devoted to the various methodologies used in confronting theory and experiment. Both weak-field (solar system) and strong-field (binary pulsar) tests are discussed in detail. A special discussion is devoted to the cosmology of moduli fields, i.e. scalar fields having only gravitational-strength couplings to matter.