Topological Density and Instantons on a Lattice

TL;DR

This paper investigates the topological structure of QCD on a lattice, comparing methods for calculating topological density, and analyzing instanton properties using improved gauge actions and cooling techniques.

Contribution

It introduces an improved gauge action that suppresses dislocations and compares different methods for topological density calculation in lattice QCD.

Findings

Improved gauge action reduces topological dislocations.

Cooling method effectively identifies instantons.

Calculated instanton size, density, and renormalization constant Z_Q.

Abstract

We present an update on the study of topological structure of QCD. Issues addressed include a comparison between the plaquette and the geometric methods of calculating the topological density. We show that the improved gauge action based on sqrt(3) blocking transformation suppresses the formation of topologically charged dislocations with low action. Using a cooling method we identify the instantons' location, estimate their size and density, and calculate the renormalization constant Z_Q for the plaquette method.