Lattice gauge theory with staggered fermions: how, where, and why (not)

TL;DR

This paper reviews the use of staggered fermions in lattice QCD, discussing the validity of the rooting procedure, recent improvements, and its importance for particle physics research.

Contribution

It provides a comprehensive survey of evidence supporting the rooting procedure and addresses recent criticisms, highlighting algorithmic and technical advancements.

Findings

Evidence supports the validity of the rooting procedure.

Recent algorithmic improvements enhance simulation accuracy.

Staggered fermions are crucial for broad particle physics results.

Abstract

Many results from lattice QCD of broad importance to particle and nuclear physics are obtained with 2+1 flavors of staggered sea quarks. In the continuum limit, staggered fermions yield four species, called tastes. To reduce the number of tastes to one (per flavor), the simulation employs the fourth root of the four-taste staggered fermion determinant. This talk surveys evidence in favor of this procedure, refutes recent criticisms, and reviews recent algorithmic and technical improvements. Physics results are covered in other plenary talks.