Research Projects

The LCDM (cosmological constant Lambda + cold dark matter) model, based on Einstein's general theory of relativity, is a mathematically tractable and observationally testable model of the Universe. It has been successful in explaining various features of the Universe, such as cosmic acceleration and large scale structure formation. However, improvements in estimating uncertainties have led to significant tensions in the measurement of quantities between Planck and independent cosmological probes. The most significant tension is in the estimation of the Hubble constant H0 between the Cosmic Microwave Background (CMB) and direct local distance ladder measurements. The Planck collaboration constraint is currently in tension at about 4.2 sigma with the 2020 SH0ES collaboration constraint, based on analysis of Hubble Space Telescope observations using Cepheids observations. Measurements from other approaches also prefer higher values of H0 compared to the H0 value derived from the Planck CMB LCDM. The discrepancy between the estimates of Hubble constant H0 within the LCDM model and direct local measurements is a major concern in modern cosmology. It is unclear whether these inconsistencies are due to systematics in the data or need some physics beyond the standard LCDM model. Therefore, it is important to develop and study physically realistic cosmological models beyond the LCDM model relaxing the H0 tension in general relativity and modified theories of gravity. This proposal is part of the common mission of the research community to address the issues of LCDM cosmology and aims to advance research on the H0 tension by providing solutions to this potential tension.