Cosmological perturbations and short distance physics from Noncommutative Geometry

TL;DR

This paper explores how noncommutative geometry at short distances could influence inflationary perturbations, potentially affecting the cosmic microwave background's statistical properties.

Contribution

It introduces a nonlocal inflaton action derived from noncommutative geometry and analyzes its impact on primordial fluctuations and CMB spectra.

Findings

Noncommutative effects alter the gaussianity of fluctuations

Spacetime noncommutativity impacts isotropy of perturbations

Potential signatures in the CMB spectrum are identified

Abstract

We investigate the possible effects on the evolution of perturbations in the inflationary epoch due to short distance physics. We introduce a suitable non local action for the inflaton field, suggested by Noncommutative Geometry, and obtained by adopting a generalized star product on a Friedmann-Robertson-Walker background. In particular, we study how the presence of a length scale where spacetime becomes noncommutative affects the gaussianity and isotropy properties of fluctuations, and the corresponding effects on the Cosmic Microwave Background spectrum.