Orateur
Description
In the quest to establish possible imprints of quantum gravity we consider so-called minisuperspace models that should be understood as a low energy limit of a full quantum gravitational theory. Starting from a bouncing minisuperspace model that resolves the big bang singularity, we will relax the assumption that the state of the quantum universe has to correspond to a single highly semiclassical state. Instead, we will consider a universe in a superposition of such states.
Faced with the question of how to extract a semiclassical scale factor that can be connected to the classical evolution of general relativity, we propose to make use of the trajectory approach to quantum mechanics. We illustrate the treatment of cosmological perturbations over a superposition background described by a trajectory and consider implications for the resulting power spectrum. Notably these spectra can exhibit features that significantly differ from the single state case.