Accelerated overlap fermions
Adams, David H.
Date of Issue2002
School of Physical and Mathematical Sciences
Numerical evaluation of the overlap Dirac operator is difficult since it contains the sign function ε(H w ) of the Hermitian Wilson-Dirac operator H w with a negative mass term. The problems are due to H w having very small eigenvalues on the equilibrium background configurations generated in current day Monte Carlo simulations. Since these are a consequence of the lattice discretization and do not occur in the continuum version of the operator, we investigate in this paper to what extent the numerical evaluation of the overlap can be accelerated by making the Wilson-Dirac operator more continuum-like. Specifically, we study the effect of including the clover term in the Wilson-Dirac operator and smearing the link variables in the irrelevant terms. In doing so, we have obtained a factor of 2 speedup by moving from the Wilson action to a fat link irrelevant clover action as the overlap kernel.
Physical and Mathematical Sciences
Physical review D
© 2002 The American Physical Society. This paper was published in Physical Review D and is made available as an electronic reprint (preprint) with permission of The American Physical Society. The paper can be found at the following official DOI: http://dx.doi.org/10.1103/PhysRevD.66.014501. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.