Weighing the spatial and temporal fluctuations of the dark universe

A generic prediction of the standard cosmology, based on general relativity (GR), dark matter and the cosmological constant (and more generally, smooth dark energy), is that, the two gravitational potentials describing the spatial and temporal scalar perturbations of the universe are equivalent. Modifications in GR or dark energy clustering in general violate this relation. Thus this ratio serves as a smoking gun of the dark universe. We propose a method to extract this ratio at various cosmological scales and redshifts from a set of measurements, in a model independent way. The ratio measured by future surveys has strong discriminating power for a variety of dark universe scenarios.