Unparticles and inflation

TL;DR

This paper explores the potential role of unparticles in inflationary cosmology, showing that while unparticles alone don't produce observed perturbations, their coupling to inflatons can subtly modify the primordial power spectrum.

Contribution

It provides a detailed analysis of loop corrections from unparticles to the inflaton's power spectrum, highlighting their dependence on unparticle scaling dimensions and wavelength.

Findings

Unparticles alone do not match observed primordial perturbations.

Coupling unparticles to inflatons can enhance the power spectrum at long wavelengths.

Power spectrum divergence occurs when unparticle scaling dimension exceeds 1.5.

Abstract

We study some of the roles for unparticles in an inflationary universe. Unparticles by themselves are not appropriate for generating the primordial perturbations since their power spectrum does not match what has been inferred from observations. In fact, when the scaling dimension for the unparticles exceeds three-halves, the unparticle power spectrum diverges. However, when a unparticle couples to an ordinary inflaton particle, loop corrections can produce a slight enhancement of the inflaton's power spectrum at longer wavelengths. We examine these loop corrections from unparticles in some detail to learn how they scale in the wavelength of a perturbation and how they depend on the scaling dimension of the field.