Density Perturbations of Quantum Mechanical Origin and Anisotropy of the Microwave Background

TL;DR

This paper discusses how large-scale anisotropies in the cosmic microwave background are likely caused by quantum-origin gravitational waves rather than density or rotational perturbations.

Contribution

It proposes that quantum-mechanical long-wavelength perturbations responsible for CMB anisotropy are predominantly gravitational waves.

Findings

Gravitational waves are the most probable quantum-origin perturbations causing CMB anisotropy.

Density and rotational perturbations are less likely to be the main cause.

Quantum mechanical origin of perturbations influences the anisotropy pattern.

Abstract

If the large-angular-scale anisotropy in the cosmic microwave background radiation is caused by the long-wavelength cosmological perturbations of quantum mechanical origin, they are, most likely, gravitational waves, rather than density perturbations or rotational perturbations.