Hubble Tension: The Evidence of New Physics

The lambda CDM model provides a good fit to most astronomical observations but harbors large areas of phenomenology and ignorance. With the improvements in the precision and number of observations, discrepancies between key cosmological parameters of this model have emerged. Among them, the most notable tension is the 4 sigma to 6 sigma deviation between the Hubble constant (H0) estimations measured by the local distance ladder and the cosmic microwave background (CMB) measurement. In this review, we revisit the H0 tension based on the latest research and sort out evidence from solutions to this tension that might imply new physics beyond the lambda CDM model. The evidence leans more towards modifying the late-time universe.

Automated summary

The lambda CDM model fits most astronomical observations well but still contains areas of unknown phenomenology. With improved precision and number of observations, discrepancies in key cosmological parameters have emerged, particularly the significant deviation of 4 sigma to 6 sigma between the Hubble constant (H0) estimations from the local distance ladder and the cosmic microwave background (CMB) measurement. This review focuses on reevaluating the H0 tension and identifying evidence for new physics beyond the lambda CDM model, which leans towards modifications in the late-time universe.