*Room change: The talk will be held in L5D23, the large seminar room on level D of Lab 5*

Speaker: Masazumi Honda

Title: Resurgence and Exact results in Supersymmetric gauge theories

Abstract: In the past decades, there appeared many exact results in supersymmetric gauge theories thanks to localization method. These exact results are useful to study properties of perturbative series in quantum field theory (QFT) especially in the following two senses. First we can systematically analyze perturbative series around (non-)trivial saddle points in QFT. Second when we manage to obtain resummation of perturbative series without ambiguities in someway (e.g. Borel resummation and resurgence), one can explicitly see how the resummation is related to the exact result including non-perturbative corrections. In my talk I will demonstrate this in 3d N=2, 4d N=2 and 5d N=1 supersymmetric gauge theories. I will first discuss that we can show Borel summability of perturbative series by Yang-Mills coupling along real positive axis in 4d N=2 and 5d N=1 supersymmetric gauge theories with Lagrangians for various observables. It turns out that exact results in these theories can be obtained by summing over the Borel resummations with every instanton number. I will also discuss perturbative series in general 3d N=2 supersymmetric Chern-Simons matter theory, which is given by a power series expansion of inverse Chern-Simons levels. For this case we can prove that the perturbative series are always Borel summable along imaginary axis while it is not Borel summable along real positive axis often. It turns out that the Borel resummations along this direction are the same as the exact results. I will also explain physical interpretations of infinite singularities in Borel plane and Lefschetz thimble structures for this class of theories.

Profile: Masazumi Honda is an assistant professor at Yukawa Institute for Theoretical Physics and visiting scientist at RIKEN iTHEMS. He is interested in quantum field theory, string theory, quantum gravity, resurgence and quantum information theory. He received his Ph.D. in 2013 at SOKENDAI & KEK under the supervision of Jun Nishimura. In the context of resurgence, he wrote several papers on applications to supersymmmetric gauge theories. He recently started to work also on applications to cosmology and quantum gravity. Private website

This seminar is a part of the first TSVP Thematic Program "Exact Asymptotics: From Fluid Dynamics to Quantum Geometry" (https://groups.oist.jp/tsvp/exact-asymptotics). OIST students and researchers are welcome to participate in all scientific sessions of the program without registration.

List and profiles of program participants can be found here: https://groups.oist.jp/tsvp/23ea-program-participants