01:25:59
published on July 7, 2026
EFT of Open Systems : Path Integrals and the Schwinger–Keldysh Formalism (2/4)
By Enrico Pajer
EFT of Open Systems : Open Gauge Theories and Cosmological Goldstone Modes (3/4)
By Enrico Pajer
Appears in collection : 2026 IHES Summer School – Cosmological Correlators
This lecture focuses on general structural aspects of open quantum field theories, with particular emphasis on open gauge theories. Topics include: - A systematic algorithm to count physical degrees of freedom in open theories, - Constraints, gauge symmetries, and gauge identities in the advanced and retarded sectors , - The open effective theory of the Nambu–Goldstone boson associated with broken time translations with aplications to inflationary cosmology, - Implications for primordial perturbations and cosmological correlators in the presence of dissipation and noise.
