Role of the Wilson mass parameter in the overlap Dirac topological charge density

Abstract

The negative Wilson mass parameter is an input parameter to the overlap Dirac operator. We examine the extent to which the topological charge density, revealed by the overlap definition, depends on the value of the negative Wilson mass. A strong dependence is observed, which can be correlated with the topological charge density obtained from the gluonic definition, with a variable number of stout-link smearing sweeps. The results indicate that the freedom typically associated with fat-link fermion actions, through the number of smearing sweeps, is also present in the overlap formalism, through the freedom in the Wilson mass parameter.

Comments: (v2) Minor changes to the introductory text. Added a Ref. (v1) 7 pages, 4 figures, presented at the XXVII International Symposium on Lattice Field Theory - LAT2009, July 26-31 2009, Peking University, Beijing, China