Enrico Pajer - Field Theory in Cosmology

These lectures introduce quantum field theory methods for early-universe cosmology, in particular the quantum generation of primordial perturbations during inflation. After a brief review of cosmology, we learn how to quantize scalars and gravitons in curved spacetime and compute cosmological correlators using the in-in (canonical) formalism. We briefly discuss the effective field theory approach to gravity and derive predictions for primordial non-Gaussianity, primarily bispectra. The notes conclude with a discussion of cosmological soft theorems and Maldacena's consistency relation.


Field Theory in Cosmology lecture notes (PDF)


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Contents

  1. A quick review of background cosmology
  2. Free fields on curved backgrounds
  3. Interacting fields and the in-in formalism
  4. Correlators from P(X,phi) theories
  5. Gravity
  6. Symmetries and soft theorems
  7. Phenomenology

Problem Sheets

These example sheets are from the Lent Term 2020 and 2021 versions of the course.