Error reduction technique using covariant approximation and application to nucleon form factor

TL;DR

This paper introduces an advanced variance reduction method called all-mode averaging (AMA) for lattice QCD calculations, significantly improving the efficiency of computing nucleon form factors by reducing statistical noise.

Contribution

The paper applies AMA to hadron propagators and nucleon form factors in lattice QCD, demonstrating its superior efficiency over existing techniques like LMA and source-shift methods.

Findings

AMA reduces statistical errors more effectively than LMA and source-shift methods.

AMA is more cost-effective for hadron two- and three-point functions.

The technique enhances the accuracy of nucleon form factor calculations.

Abstract

We demonstrate the new class of variance reduction techniques for hadron propagator and nucleon isovector form factor in the realistic lattice of $N_f=2+1$ domain-wall fermion. All-mode averaging (AMA) is one of the powerful tools to reduce the statistical noise effectively for wider varieties of observables compared to existing techniques such as low-mode averaging (LMA). We adopt this technique to hadron two-point functions and three-point functions, and compare with LMA and traditional source-shift method in the same ensembles. We observe AMA is much more cost effective in reducing statistical error for these observables.