Inflationary scalar spectrum in loop quantum cosmology

TL;DR

This paper investigates the scalar perturbation spectrum during inflation in loop quantum cosmology, highlighting how quantum effects influence spectral tilt and the necessity of tuning quantization parameters for observational consistency.

Contribution

It extends the analysis of scalar spectra in loop quantum cosmology to generalized quantization schemes, exploring the impact of quantum ambiguities on inflationary predictions.

Findings

Scalar spectrum can be blue-tilted and deviate from scale invariance.

Tuning quantization ambiguities is necessary for observational agreement.

Quantization of matter fields at sub-horizon scales offers a consistency check.

Abstract

In the context of loop quantum cosmology, we consider an inflationary era driven by a canonical scalar field and occurring in the semiclassical regime, where spacetime is a continuum but quantum gravitational effects are important. The spectral amplitude and index of scalar perturbations on an unperturbed de Sitter background are computed at lowest order in the slow-roll parameters. The scalar spectrum can be blue-tilted and far from scale invariance, and tuning of the quantization ambiguities is necessary for agreement with observations. The results are extended to a generalized quantization scheme including those proposed in the literature. Quantization of the matter field at sub-horizon scales can provide a consistency check of such schemes.