Novel vacuum conditions in inflationary collapse models

TL;DR

This paper explores how a novel initial quantum state in inflationary models with wave function collapse can produce a scale-invariant primordial power spectrum and align with CMB observations, suggesting a fundamental collapse mechanism.

Contribution

It introduces a new vacuum state selection method based on a Hadamard procedure for inflationary collapse models, improving upon the traditional Bunch-Davies vacuum approach.

Findings

The new vacuum state yields an almost scale-free primordial spectrum.

The model's CMB angular spectrum matches observational data.

Collapse timing parameters are consistent with previous models.

Abstract

Within the framework of inflationary models that incorporate a spontaneous reduction of the wave function for the emergence of the seeds of cosmic structure, we study the effects on the primordial scalar power spectrum by choosing a novel initial quantum state that characterizes the perturbations of the inflaton. Specifically, we investigate under which conditions one can recover an essentially scale free spectrum of primordial inhomogeneities when the standard Bunch-Davies vacuum is replaced by another one that minimizes the renormalized stress-energy tensor via a Hadamard procedure. We think that this new prescription for selecting the vacuum state is better suited for the self-induced collapse proposal than the traditional one in the semiclassical gravity picture. We show that the parametrization for the time of collapse, considered in previous works, is maintained. Also, we obtain an angular spectrum for the CMB temperature anisotropies consistent with the one that best fits the observational data. Therefore, we conclude that the collapse mechanism might be of a more fundamental character than previously suspected.