Schwinger-Keldysh effective field theory
APA
Jensen, K. (2017). Schwinger-Keldysh effective field theory. Perimeter Institute. https://pirsa.org/17030087
MLA
Jensen, Kristan. Schwinger-Keldysh effective field theory. Perimeter Institute, Mar. 21, 2017, https://pirsa.org/17030087
BibTex
@misc{ pirsa_PIRSA:17030087, doi = {10.48660/17030087}, url = {https://pirsa.org/17030087}, author = {Jensen, Kristan}, keywords = {Quantum Fields and Strings}, language = {en}, title = {Schwinger-Keldysh effective field theory}, publisher = {Perimeter Institute}, year = {2017}, month = {mar}, note = {PIRSA:17030087 see, \url{https://pirsa.org}} }
The subject of quantum field theory in mixed states of quantum matter is an old and rich one. The natural setting to discuss field theory in a mixed state is the Schwinger-Keldysh formalism. The subject of this talk is the set of peculiar symmetries that arise in Schwinger-Keldysh theories, and how they may be accounted for in effective field theory. In particular, when the mixed state is thermal, the effective description is constrained by two BRST-like supercharges which, at low energies, generate an algebra akin to minimal supersymmetric quantum mechanics. If time allows, I will also discuss a sort of Schwinger-Keldysh bootstrap for effective actions on more complicated closed-time-contours, which describe the out-of-time-ordered correlation functions that diagnose early-time chaotic growth in quantum systems.