The application of weak lensing

Gravitational lensing distorts cosmic shear maps and Cosmic Microwave Background (CMB) anisotropies maps. We derive the correlation functions of the lensing-induced shear and the reconstructed deflection angle. We investigate the applications of those correlations in determining cosmological parameters: (1) The reconstructed lensing potential enhances the detectability of CMB tensor B-mode anisotropy which completes all required initial conditions to explain the primordial universe. (2) The cross-correlation between the lensed CMB maps and Far Infrared Radiation Background (FIRB) anisotropy maps is studied to understand the nature of FIRB sources and their relation to the distribution of dark matter. (3) CMB lensing and cosmic shear can be used to probe massive neutrinos collapsing into the gravitational wells when they become non-relativistic. (4) The cosmological parameters related to cosmic acceleration can be precisely determined by cosmic shear maps. We study how to generalise those parameters and how to discriminate different models.