Exploring Lattice Quantum Chromodynamics by Cooling

TL;DR

This paper investigates the effects of cooling on various observables in SU(2) lattice gauge theory, revealing how cooling diminishes interactions and alters hadron correlators, raising questions about the interpretation of these changes.

Contribution

It provides a detailed analysis of how cooling impacts key observables in lattice QCD, including the static potential, topological charge, and meson correlators, highlighting the rapid disappearance of interactions.

Findings

Cooling eliminates interactions on small distance scales.

Meson correlators relax quickly to free-field behavior.

Large-time behavior of correlators differs from uncooled masses.

Abstract

The effect of cooling on a number of observables is calculated in SU(2) lattice gauge theory. The static quark-antiquark potential and spin-dependent interactions are studied, and the topological charge is monitored. The chiral symmetry breaking order parameter $\langle \overline{\chi}\chi \rangle$ and meson correlators are calculated using staggered fermions. Interactions on the distance scale of a few lattice spacings are found to be essentially eliminated by cooling, including the spin-dependent potentials. $\langle \overline{\chi}\chi \rangle$ and meson correlators up to time separations of several lattice spacings relax very quickly to their free-field values. At larger times, there is evidence of a difference between the pseudoscalar and vector channels. A fit to the pseudoscalar correlation function yields ``mass'' values about $2/3$ (in lattice units) of the uncooled masses. These results raise the question of how to reconcile the large-time behavior of the hadron correlators with the fact that the spin-dependent potentials and $\langle \overline{\chi}\chi \rangle$ essentially disappear (in lattice units) after only a small amount of cooling.