Loop quantum cosmology, non-Gaussianity, and CMB power asymmetry

TL;DR

This paper proposes that the observed CMB power asymmetry may originate from a cosmic bounce in loop quantum cosmology, which induces scale-dependent non-Gaussian correlations and large-scale dipole modulations consistent with observations.

Contribution

It demonstrates how quantum gravitational effects in LQC can produce observable non-Gaussian features and asymmetries in the CMB through a bounce scenario.

Findings

LQC bounce leads to scale-dependent non-Gaussianity.

Correlations across observable and super-horizon modes.

Induces large-scale dipole modulation in CMB.

Abstract

We argue that the anomalous power asymmetry observed in the cosmic microwave background (CMB) may have originated in a cosmic bounce preceding inflation. In loop quantum cosmology (LQC) the big bang singularity is generically replaced by a bounce due to quantum gravitational effects. We compute the spectrum of inflationary non-Gaussianity and show that strong correlation between observable scales and modes with longer (super-horizon) wavelength arise as a consequence of the evolution of perturbations across the LQC bounce. These correlations are strongly scale dependent and induce a dipole-dominated modulation on large angular scales in the CMB, in agreement with observations.