The QFT-core seminar series has been started from this fiscal year. The seminar series is hold under the theme of the Quantum Field Theory including elementary particle theory, nuclear theory and Condensed Matter physics.

The First seminar in the series was given by Dr.Kengo Kikuchi from the Riken iTHEMS on May 15. The title is “Gradient Flow Equation and Its Applications”. The gradient flow is the one of the methods to suppress the ultraviolet divergence in gauge theories. The any correlation functions in terms of the flowed field, which is defined by the gradient flow equation, are finite without additional renormalizations. Because of this surprising property, the methods has been studied widely, especially in the lattice field theory. In this seminar, he introduce what the gradient flow is briefly, and show his work, “generalized gradient flow equation”, which is the gradient flow equation for field theories with nonlinearly realized symmetry. Applying the formalism to a supersymmetric theory and O(N) non linear sigma model, the SUSY gradient flow and the Large N gradient flow are obtained. He also refer to the current research, the gradient flow of the supersymmetric theory with the non-renormalization theorem and the new formalism to obtain the sphalerons, which is one of the static classical solutions, using gradient flow methods.

The seminar was hold via Zoom. There were about 20 participants from iTHEMS and other university. The participants enjoyed meaningful discussions through the seminar.