Approaching the master-field: Hadronic observables in large volumes

TL;DR

This paper explores the master-field approach in lattice QCD, demonstrating how to efficiently compute hadronic observables on large volumes using single configurations, and analyzing error scaling and measurement strategies.

Contribution

It introduces methods for calculating hadronic quantities in the master-field approach, focusing on error estimation and comparison of different two-point function techniques.

Findings

Position-space correlators show promising results at intermediate volumes.

Error scaling with volume is analyzed and optimized.

Technical challenges like boundary effects are addressed.

Abstract

The master-field approach to lattice QCD envisions performing calculations on a small number of large-volume gauge-field configurations. Substantial progress has been made recently in the generation of such fields, and this must be joined with measurement strategies that take advantage of the large volume. In these proceedings, we describe how to compute simple hadronic quantities efficiently and estimate their errors in the master-field approach, i.e. by studying cross-correlations of observables on a single configuration. We discuss the scaling of the uncertainty with the volume and compare extractions based on momentum-projected and position-space two-point functions. The latter show promising results, already at intermediate volumes, but come with additional technical complexities such as a more complicated manifestation of boundary effects, which we also address.