Testing Topology Conserving Gauge Actions for Lattice QCD

TL;DR

This paper investigates gauge actions in lattice QCD that suppress small plaquette values to better conserve topological charge, aiming to improve numerical stability and accuracy in simulations involving dynamical quarks.

Contribution

It introduces and tests topology conserving gauge actions based on the admissibility condition, demonstrating their benefits in lattice QCD simulations.

Findings

Stable topological charge history observed.

Improved condition number of the overlap operator kernel.

Acceptable acceptance rates in HMC simulations.

Abstract

We explore gauge actions for lattice QCD, which are constructed such that the occurrence of small plaquette values is strongly suppressed. Such actions originate from the admissibility condition in order to conserve the topological charge. The suppression of small plaquette values is expected to be advantageous for numerical studies in the $\epsilon$-regime and also for simulations with dynamical quarks. Performing simulations at a lattice spacing of about 0.1 fm, we present numerical results for the static potential, the physical scale $r_0$, the stability of the topological charge history, the condition number of the kernel of the overlap operator and the acceptance rate against the step size in the local HMC algorithm.