Cosmological gravity probes: connecting recent theoretical developments to forthcoming observations

Understand

Since the discovery of the accelerated expansion of the present Universe, significant theoretical developments have been made in the area of modified gravity.

• In the meantime, cosmological observations have been providing more high-quality data, allowing us to explore gravity on cosmological scales.
• To bridge the recent theoretical developments and observations, we present an overview of a variety of modified theories of gravity and the cosmological observables in the cosmic microwave background and large-scale structure, supplemented with a summary of predictions for cosmological observables derived from cosmological perturbations and sophisticated numerical studies.
• We specifically consider scalar-tensor theories in the Horndeski and DHOST family, massive gravity/bigravity, vector-tensor theories, metric-affine gravity, and cuscuton/minimally-modified gravity, and discuss the current status of those theories with emphasis on their physical motivations, validity, appealing features, the level of maturity, and calculability.