Inhomogeneities from quantum collapse scheme without inflation

TL;DR

This paper explores a non-inflationary cosmological model where quantum wave function collapse leads to primordial inhomogeneities, analyzing conditions for scale invariance and deviations from it.

Contribution

It introduces a spontaneous wave function reduction mechanism into the Hollands and Wald model to generate cosmic structure seeds without inflation.

Findings

Conditions for scale-free primordial spectrum identified

Deviations from scale invariance analyzed

Impact of quantum collapse on inhomogeneity spectrum studied

Abstract

In this work, we consider the problem of the emergence of seeds of cosmic structure in the framework of the non-inflationary model proposed by Hollands and Wald. In particular, we consider a modification to that proposal designed to account for breaking the symmetries of the initial quantum state, leading to the generation of the primordial inhomogeneities. This new ingredient is described in terms of a spontaneous reduction of the wave function. We investigate under which conditions one can recover an essentially scale free spectrum of primordial inhomogeneities, and which are the dominant deviations that arise in the model as a consequence of the introduction of the collapse of the quantum state into that scenario.