Update on the sea contributions to hadron polarizabilities via reweighting

TL;DR

This paper advances lattice QCD calculations of hadron polarizabilities by incorporating sea quark effects through perturbative reweighting, employing aggressive stochastic estimation techniques to improve accuracy.

Contribution

It introduces a novel reweighting method for sea quark effects in polarizability calculations, utilizing aggressive dilution schemes and low-mode substitution to reduce stochastic noise.

Findings

Neutron polarizability measured as 2.70(55) * 10^-4 fm^3

Demonstrated effectiveness of dilution and low-mode substitution techniques

Introduced offdiagonal matrix element mapping for estimator prediction

Abstract

We have made significant progress on extending lattice QCD calculation of the polarizability of the neutron and other hadrons to include the effects of charged dynamical quarks. This is done by perturbatively reweighting the charges of the sea quarks to couple them to the background field. The dominant challenge in such a calculation is stochastic estimation of the weight factors, and we discuss the difficulties in this estimation. Here we use an extremely aggressive dilution scheme with N = 124,416 sources per configuration to reduce the stochastic noise to a manageable level. We find that \alpha_E = 2.70(55) * 10^-4 fm^3 for the neutron on one ensemble. We show that low-mode substitution can be used in tandem with dilution to construct an even better estimator, and introduce the offdiagonal matrix element mapping technique for predicting estimator quality.