Speaker
Description
We use the Euclidean path-integral method to approximate the wave function of the Universe and consider the particular scenario in which a Euclidean wormhole instanton dominates. This Euclidean wormhole solution connected to Lorentzian manifolds provides an approximation to the emergence of a classical spacetime in the quantum cosmological treatment. Beyond the background level, perturbations built on top of this instanton solution are treated quantum mechanically in both the Euclidean and Lorentzian regimes. Due to the existence of a Euclidean wormhole bridging the twin universes, the perturbations of each universe is then in a mixed-state and the mutual entanglement shall leave signatures in the cosmic microwave background (CMB) power spectrum. Invoking the Klebanov-Susskind-Banks wormhole as a toy model for the sake of tractability, we show that the entanglement selects a novel and unique non-thermal global vacuum for the total inflaton perturbations in both universes.