Nonvacuum initial states for cosmological perturbations of quantum-mechanical origin - art. no. 083518

In the context of inflation. nonvacuum initial states for cosmological pert urbations that possess a built in scale are studied. It is demonstrated tha t this assumption leads to a falsifiable class of models. The question of w hether they lead to conflicts with the available observations is addressed. For this purpose, the power spectrum of the Bardeen potential operator is calculated and compared with the CMBR anisotropies measurements and the red shift surveys of galaxies and clusters of galaxies. Generic predictions of the model are a high first acoustic peak, the presence of a bump in the mat ter power spectrum and non-Gaussian statistics. The details are controlled by the number of quanta in the nonvacuum initial state. Comparisons with ob servations show that there exists a window for the free parameters such tha t good agreement between the data and theoretical predictions is possible. However, in the case where the initial state is a state with a fixed number of quanta. it is shown that this number cannot be greater than a few. On t he other hand, if the initial state is a quantum superposition. then a larg er class of initial states could account fur the observations. even though the stare cannot be too different from the vacuum. Planned missions such as the MAP and Planck satellites and the Sloan Survey will demonstrate whethe r the new class of models proposed hete represents a viable alternative to the standard theory.