Direct signature of an evolving gravitational potential from the cosmic microwave background - art. no. 043504

We show that a time dependent gravitational potential can be directly detec ted from cosmic microwave background (CMB) anisotropies. The signature can be measured by cross-correlating the CMB with the projected density field r econstructed from weak lensing distortions of the CMB itself. The cross-cor relation gives a signal whenever there is a time dependent gravitational po tential. This method traces dark matter directly and has a well defined red shift distribution of mass producing the lensing, thereby avoiding the prob lems plaguing other proposed cross-correlations. We show that both the Micr owave Anisotropy Probe (MAP) and Planck satellites will be able to probe th is effect for observationally relevant curvature and cosmological constant models, which will provide additional constraints on the cosmological param eters. [S0556-2821(99)00216-7].