Nagoya University: Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI)

JICFuS Seminar on Non-perturbative Physics@KMI

"Recent progress in lattice fermion formulations"

Tatsuhiro Misumi

(Keio University)

July 17, 2013 (Wed) 15:00-

KMI Science Symposia (ES635)

Abstract:
We review the recent progress in lattice fermion discretizations and discuss their application to numerical calculations. We introduce several novel concepts to improve and extend lattice study:

Lattice flavored mass is a generalization of the Wilson term, which yields species-splitting to extract desirable number of flavors both in naive and staggered fermions. It leads to a variety of improved Wilson and overlap fermions, and they can reduce numerical cost in overlap-fermion lattice QCD and lighten the technical difficulty for heavy quark systems.
Central-branch fermion is another way of use of Wilson-type fermions. It possesses exact axial symmetry forbidding additive mass renormalization and does not require fine-tuning in lattice QCD. It could give us a new tool to study many-flavor QCD, including 6-, 10- and 12-flavor systems.
We also look into implication of SUSY lattice formulations on fermion discretizations.
We lastly discuss a totally different aspect of lattice fermions related to the sign problem: numerical Grassmann integral.

All of these ideas reveal unknown aspects of lattice fermions, and leads us to deeper understanding of lattice field theory.

Slide