The cosmic microwave background (CMB) is one of the most precise measurements ever made in cosmology. It is great success of LCDM to explain the observed CMB spectra with only six parameters. However, recent study of the cosmological tensions, especially that of early dark energy, reveals the fact that even CMB can accommodate beyond a LCDM dark component occupying up to 10% of the total energy budget during recombination when the CMB is generated. This opens up an important window of studying modified gravity before and near recombination. In this talk, I will discuss some of my recent findings about modified gravity, within the framework of scalar-tensor theories, in light of recent BAO, SNIa and CMB observations. I will show that modified gravity might play an important role in restoring concordance from the cosmological tensions.

Biography

Dr. Ye got his Bachelor’s degree in 2018 and Ph.D. in 2022 under the supervision of Prof. Yun-Song Piao at the University of Chinese Academy of Sciences, then moved to Leiden University as a postdoctoral researcher. His research interest lies on probing the fundamental laws of physics with cosmological observations, with an emphasis on gravity and the cosmological tensions. He has discovered the possible connection between the Hubble tension, the anti-de Sitter vacuum and the axion of mass 10^-26 eV. He has also developed a novel way of observing early Universe physics through resonance in the gravitational wave background. His recent research uncovered evidence of modification to general relativity in the new cosmological observations, which might be the key to restoring cosmological concordance.

Inviter

Shao-Jiang Wang