Speaker
Description
Fifth forces are ubiquitous in modified theories of gravity. In this talk, I present our recent results investigating their effect on the Cepheid-calibrated cosmic distance ladder, specifically with respect to the inferred value of the Hubble constant (H0). We consider a variety of effective models where the strength of the fifth force is estimated using proxy fields related to the large-scale structure of the Universe. For all models considered, the local distance ladder and the Planck value for H0 agrees with a probability >20%, relieving the tension compared to the concordance model with data being excluded at 99% confidence. The alleviated discrepancy comes partially at the cost of an increased tension between distance estimates from Cepheids and tip of the red-giant branch stars (TRGB). Demanding also that the consistency between the Cepheid and TRGB distance estimates is not impaired, models can still accommodate the data with a probability >20%. This provides incentive for more detailed investigations of fundamental theories on which the effective fifth force models are based, and their effect on the Hubble tension.
