Lectures were given at the Italian Society of Gravitational Physics Summer School "Relativistic Cosmology: Theory and Observation" in Como, Italy (May 2000); preprint no. RAP-290. astro-ph/0102402

E-mail: kosowsky@physics.rutgers.edu

**Abstract:** This set of lectures provides an overview of the
basic theory and phenomenology of the cosmic microwave background.
Topics include a brief historical review; the physics of
temperature and polarization fluctuations; acoustic oscillations of
the primordial plasma; the space of inflationary cosmological
models; current and potential constraints on these models from
the microwave background; and constraints on inflation.
These lectures were given at the Italian Society of Gravitational
Physics Summer School "Relativistic Cosmology:
Theory and Observation" in Como, Italy (May 2000).

**Table of Contents**

- INTRODUCTION
- A BRIEF HISTORICAL PERSPECTIVE
- PHYSICS OF TEMPERATURE FLUCTUATIONS
- Causes of temperature fluctuations
- A formal description
- Tight coupling
- Free streaming
- Diffusion damping
- The resulting power spectrum
- PHYSICS OF POLARIZATION FLUCTUATIONS
- Stokes parameters
- Thomson scattering and the quadrupolar source
- Harmonic expansions and power spectra
- ACOUSTIC OSCILLATIONS
- COSMOLOGICAL MODELS AND CONSTRAINTS
- A space of models
- Physical quantities
- Power spectrum degeneracies
- Idealized experiments
- Current constraints and upcoming experiments
- MODEL-INDEPENDENT COSMOLOGICAL CONSTRAINTS
- Flatness
- Coherent acoustic oscillations
- Adiabatic primordial perturbations
- Gaussian primordial perturbations
- Tensor or vector perturbations
- Reionization redshift
- Magnetic Fields
- The topology of the universe
- FINALE: TESTING INFLATIONARY COSMOLOGY
- REFERENCES