Title: Going with the flow: complexification of path integrals and the sign problem
Abstract :In this talk, I will explore the generalization of the Feynman path integral in quantum field theory to complexified fields. The approach is based on a deep connection between holomorphic functions and topology (known as the Picard-Lefschetz theory) which has profound implications for quantum field theory and string theory. After introducing the basic concepts that link Picard-Lefcshetz theory to the Feynman path integral, I will focus on a set of surprising applications of this framework to the real-time dynamics of quantum field theory and studies of quantum field theory at finite temperature and density. This approach has a broad range of promising potential applications ranging from high energy physics to condensed matter physics.