Physics of the cosmic microwave background anisotropy

TL;DR

This paper reviews the physics behind the cosmic microwave background's anisotropies, discussing how they inform cosmological models, the current experimental status, and challenges like foreground emissions affecting future polarization measurements.

Contribution

It provides a comprehensive overview of CMB physics, experimental techniques, and foreground challenges, emphasizing polarization and B mode detection for advancing cosmology.

Findings

CMB anisotropies encode early universe physics

Foreground emissions, especially polarized dust, are critical for B mode detection

Current and future experiments aim to improve polarization measurements

Abstract

Observations of the cosmic microwave background (CMB), especially of its frequency spectrum and its anisotropies, both in temperature and in polarization, have played a key role in the development of modern cosmology and our understanding of the very early universe. We review the underlying physics of the CMB and how the primordial temperature and polarization anisotropies were imprinted. Possibilities for distinguishing competing cosmological models are emphasized. The current status of CMB experiments and experimental techniques with an emphasis toward future observations, particularly in polarization, is reviewed. The physics of foreground emissions, especially of polarized dust, is discussed in detail, since this area is likely to become crucial for measurements of the B modes of the CMB polarization at ever greater sensitivity.