Searching for a matter bounce cosmology with low redshift observations

Abstract

The matter bounce scenario allows for a sizable parameter space where cosmological fluctuations originally exited the Hubble radius when the background energy density was small. In this scenario and its extended versions, the low energy degrees of freedom are likely responsible for the statistical properties of the cosmic microwave background power spectrum at large length scales. An interesting consequence is that these modes might be observable only at relatively late times. Therefore low redshift observations could provide evidence for, or even falsify, various bouncing models. We provide an example where a recently hinted potential deviation from $\Lambda$-cold-dark-matter cosmology results from a dark matter and dark energy interaction. The same interaction allows matter bounce models to generate a red tilt for the primordial curvature perturbations in corroboration with cosmic microwave background experiments.