Recent progress in lattice fermion formulations
KMI Theory Seminar
KMI Science Symposia (ES635)
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.