Lattice gauge action suppressing near-zero modes of H{sub W}
- Theoretical Physics Laboratory, RIKEN, Wako 351-0198 (Japan)
- High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan)
- Department of Physics, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan)
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)
We propose a lattice action including unphysical Wilson fermions with a negative mass m{sub 0} of the order of the inverse lattice spacing. With this action, the exact zero mode of the Hermitian Wilson-Dirac operator H{sub W}(m{sub 0}) cannot appear and near-zero modes are strongly suppressed. By measuring the spectral density {rho}({lambda}{sub W}), we find a gap near {lambda}{sub W}=0 on the configurations generated with the standard and improved gauge actions. This gap provides a necessary condition for the proof of the exponential locality of the overlap-Dirac operator by Hernandez, Jansen, and Luescher. Since the number of near-zero modes is small, the numerical cost to calculate the matrix sign function of H{sub W}(m{sub 0}) is significantly reduced, and the simulation including dynamical overlap fermions becomes feasible. We also introduce a pair of twisted mass pseudofermions to cancel the unwanted higher mode effects of the Wilson fermions. The gauge coupling renormalization due to the additional fields is then minimized. The topological charge measured through the index of the overlap-Dirac operator is conserved during continuous evolutions of gauge field variables.
- OSTI ID:
- 20873153
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 74, Issue 9; Other Information: DOI: 10.1103/PhysRevD.74.094505; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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