The locality of the fourth root of the staggered fermion determinant
in the interacting case.
Presenter: Francesca Maresca
C. Bernard, C. DeTar, F. Maresca, S. Gottlieb, L. Levkova, U.M. Heller, J.E.
Hetrick, R. Sugar, D. Toussaint, and D. Renner
Abstract: The fourth root trick in LQCD simulations with dynamical staggered fermions requires justification. For the case of noninteracting staggered
fermions, Shamir recently considered a renormalization-group blocking transformation of the conventional action (hep-lat/0412014) and showed that under
repeated blocking, the determinant approaches the decomposition det(D) =
det4 (Drg )det(T ), where Drg is a local Dirac operator and T is a local operator
containing only masses of the order of the cutoff. We are extending this study to
the fully interacting case, using a numerical approach with improved staggered
fermions, to test whether, even in the presence of interactions, the action still
tends to become diagonal in taste space under repeated blocking.
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