Observational imprints of our lost twin anti-universe

We consider observational consequences of the entanglement between our universe and a hypothetical twin anti-universe in the third quantization scheme of the canonical quantum gravity in order to make such a scenario falsifiable. Based on our recent and unique investigations we select some special form of the interuniversal interaction which allows the entanglement entropy of the pair of universes to diverge at the critical points of their classical evolution where the specific behaviour of the Hubble parameter plays the key role. We find that the modification of the cosmic microwave background (CMB) power spectrum due to the entanglement with our twin anti-universe for such models is enlarged for small modes k and small multipole numbers l. Our specific form of the interaction is then constrained by the Planck satellite data giving the interaction coupling constant bound to be λo≲O(10−56)s−3λo≲O(10−56)s−3 which is small, but not negligible compared to the inflationary contribution. Some other coupling functions which allow more critical points are also briefly commented on in the context of their observational effect on CMB and other prospective observational data.