Diseases with rooted staggered quarks

Abstract

Calculations using staggered quarks augmented with a root of the fermion determinant to reduce doubling give a qualitatively incorrect behavior in the small quark mass region. Attempts to circumvent this problem for the continuum limit involve an unproven combination of unphysical states, a loss of unitarity, and a rather peculiar non-commutation of limits.

Comments: 5 pages, 1 figure; poster at LATTICE '06, Tucson, Arizona, July 23-28, 2006