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 αE = 2.70(55) × 10∼-4fm3 for the neutron on one ensemble. We show that lowmode 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.
|Original language||English (US)|
|Journal||Proceedings of Science|
|State||Published - 2014|
|Event||32nd International Symposium on Lattice Field Theory, LATTICE 2014 - New York, United States|
Duration: Jun 23 2014 → Jun 28 2014
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