Inflation including collapse of the wave function: The quasi-de Sitter case

TL;DR

This paper explores how a collapse of the wave function during quasi-de Sitter inflation can produce observable deviations in the primordial power spectrum, potentially explaining CMB fluctuations.

Contribution

It extends previous collapse-based inflation models to a quasi-de Sitter background, analyzing resulting spectral deviations and their compatibility with observational data.

Findings

Most collapse schemes analyzed are consistent with CMB observations.

Deviations from scale invariance depend on the collapse scheme and quasi-de Sitter effects.

The model can distinguish itself from standard inflation by specific spectral features.

Abstract

The precise physical mechanism describing the emergence of the seeds of cosmic structure from a perfect isotropic and homogeneous universe has not been fully explained by the standard version of inflationary models. To handle this shortcoming, D. Sudarsky and collaborators have developed a proposal: the self-induced collapse hypothesis. In this scheme, the objective collapse of the inflaton wave function is responsible for the emergence of inhomogeneity and anisotropy at all scales. In previous papers, the proposal was developed with an almost exact de Sitter space-time approximation for the background that led to a perfect scale-invariant power spectrum. In the present article, we consider a full quasi-de Sitter expansion and calculate the primordial power spectrum for three different choices of the self-induced collapse. The consideration of a quasi-de Sitter background allow us to distinguish departures from an exact scale-invariant power spectrum that are due to the inclusion of the collapse hypothesis. These deviations are also different from the prediction of standard inflationary models with running spectral index. Comparison with the primordial power spectrum and the CMB temperature fluctuation spectrum preferred by the latest observational data is also discussed. From the analysis performed in this work, it follows that most of the collapse schemes analysed in this paper are viable candidates to explain present observations of the CMB fluctuation spectrum.