Watch a 34-minute conference talk from the Workshop on Phase Transitions and Topological Defects in the Early Universe where UC Berkeley's Eleanor Hall presents groundbreaking non-perturbative methods for studying false vacuum decay. Explore how the quasi-stationary effective action (QSEA) formalism integrates local field space fluctuations using functional renormalization group techniques, enabling reliable calculations of gravitational wave signals and decay rates in strongly-interacting theories. Learn about probing early universe physics through gravitational waves from phase transitions, understand the limitations of current perturbative approaches, and discover how this new methodology advances beyond traditional methods. Delve into topics including the direct method of false vacuum decay, exact effective actions, coarse graining techniques, and the implementation of functional renormalization group for fluctuations, with detailed comparisons between perturbative and non-perturbative results.
Non-perturbative Methods for False Vacuum Decay in Early Universe Phase Transitions
Harvard CMSA via YouTube
Overview
Syllabus
Intro
Probing the early universe with gravitational waves
GWs from phase transitions: theory + experiment
Theoretical outlook: work to do
False vacuum decay in the direct method
Perturbative approach: saddle point
Perturbative approach: one loop
Beyond perturbation theory: exact effective actions
BUT: exact effective actions are convex
Imperfect compromise: coarse graining
Back to the drawing board: quasi-stationary patches
Our proposal: the quasi-stationary effective action
The correct effective action for FV decay
Non-perturbative implementation: the FRG for fluctuations
Understanding the flow equation: comparison with coarse-graining
Solving the flow equation
Results and comparison with perturbation theory
The big point: decay rates for strong interactions
Understanding the fFRG flow
Taught by
Harvard CMSA
