Comment on "Chiral anomalies and rooted staggered fermions"

TL;DR

This paper refutes Creutz's claim that the rooting trick in staggered fermion simulations fails for theories with an odd number of flavors, demonstrating that the trick remains valid in the continuum limit and that taste symmetry restoration ensures unitarity.

Contribution

The authors demonstrate that Creutz's argument against the rooting trick is invalid in the continuum limit, reaffirming its validity for staggered fermion simulations.

Findings

Creutz's argument fails as the continuum limit is approached.

Taste symmetry restoration ensures unitarity in the continuum.

Rooting trick remains valid for odd number of flavors.

Abstract

In hep-lat/0701018, Creutz claims that the rooting trick used in simulations of staggered fermions to reduce the number of tastes misses key physics whenever the desired theory has an odd number of continuum flavors, and uses this argument to call into question the rooting trick in general. Here we show that his argument fails as the continuum limit is approached, and therefore does not imply any problem for staggered simulations. We also show that the cancellations necessary to restore unitarity in physical correlators in the continuum limit are a straightforward consequence of the restoration of taste symmetry.