TASI Lectures on Inflation

TL;DR

This series of lectures provides a comprehensive overview of inflationary cosmology, covering its theoretical foundations, observational evidence, and connections to fundamental physics like string theory.

Contribution

It offers an in-depth review of inflation, including detailed calculations, observational analysis, and its integration with string theory, which is a novel synthesis in the field.

Findings

Inflation solves initial conditions problems of FRW cosmology.

Primordial spectra of fluctuations are derived in detail.

Current observations support inflationary models.

Abstract

In a series of five lectures I review inflationary cosmology. I begin with a description of the initial conditions problems of the Friedmann-Robertson-Walker (FRW) cosmology and then explain how inflation, an early period of accelerated expansion, solves these problems. Next, I describe how inflation transforms microscopic quantum fluctuations into macroscopic seeds for cosmological structure formation. I present in full detail the famous calculation for the primordial spectra of scalar and tensor fluctuations. I then define the inverse problem of extracting information on the inflationary era from observations of cosmic microwave background fluctuations. The current observational evidence for inflation and opportunities for future tests of inflation are discussed. Finally, I review the challenge of relating inflation to fundamental physics by giving an account of inflation in string theory.