Lectures given at the NATO Advanced Study Institute on Techniques and Concepts of High Energy Physics, St. Croix, USVI (2002).
astro-ph/0301448.

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COSMOLOGY, INFLATION, AND THE PHYSICS OF NOTHING

William H. Kinney


Institute for Strings, Cosmology and Astroparticle Physics
Columbia University
550 W. 120th Street
New York, NY 10027
kinney@plysics.columbia.edu


Abstract. These four lectures cover four topics in modern cosmology: the cosmological constant, the cosmic microwave background, inflation, and cosmology as a probe of physics at the Planck scale. The underlying theme is that cosmology gives us a unique window on the "physics of nothing," or the quantum-mechanical properties of the vacuum. The theory of inflation postulates that vacuum energy, or something very much like it, was the dominant force shaping the evolution of the very early universe. Recent astrophysical observations indicate that vacuum energy, or something very much like it, is also the dominant component of the universe today. Therefore cosmology gives us a way to study an important piece of particle physics inaccessible to accelerators. The lectures are oriented toward graduate students with only a passing familiarity with general relativity and knowledge of basic quantum field theory.


Table of Contents

INTRODUCTION

RESURRECTING EINSTEIN'S GREATEST BLUNDER
Cosmology for beginners
Einstein's "greatest blunder"
Critical density and the return of the age problem
The vacuum in quantum field theory
Vacuum energy in cosmology

THE COSMIC MICROWAVE BACKGROUND
Recombination and the formation of the CMB
Sachs-Wolfe Effect
Acoustic oscillations and the horizon at last scattering

INFLATION
The flatness problem
The horizon problem
Inflation
Inflation from scalar fields
Density fluctuations from inflation
The primordial power spectrum
A worked example
Inflationary "zoology" and the CMB

LOOKING FOR SIGNS OF QUANTUM GRAVITY IN INFLATION

CONCLUSION

REFERENCES

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