Lecture Notes on CMB Theory: From Nucleosynthesis to Recombination

TL;DR

This paper provides a pedagogical overview of the physics and phenomenology of the cosmic microwave background during the period from nucleosynthesis to recombination, explaining how this era shapes the CMB's spectrum, temperature, and polarization anisotropies.

Contribution

It offers a comprehensive, accessible review of the physical processes during this epoch and their connection to observed CMB features, filling a gap in educational resources.

Findings

Detailed explanation of CMB spectral properties

Analysis of temperature and polarization anisotropies

Connection between physical processes and observed CMB phenomenology

Abstract

These lecture notes comprise an informal but pedagogical introduction to the well established physics and phenomenology of the cosmic microwave background (CMB) between big bang nucleosynthesis and recombination. The dominant properties of the spectrum, temperature anisotropy and polarization anisotropy of the CMB all arise from this period. We review the physical processes involved and show how they are related to the observed phenomenology.