The Shape of Covariantly Smeared Sources in Lattice QCD

Abstract

Covariantly smeared sources are commonly used in lattice QCD to enhance the projection onto the ground state. Here we investigate the dependence of their shape on the gauge field background and find that the presence of localized concentrations of magnetic field can lead to strong distortions which reduce the smearing radii achievable by iterative smearing prescriptions. In particular, as $a\to 0$, iterative procedures like Jacobi smearing require increasingly large iteration counts in order to reach physically-sized smearing radii $r_{sm}\sim$ 0.5 fm, and the resulting sources are strongly distorted. To bypass this issue, we propose a covariant smearing procedure (``free-form smearing'') that allows us to create arbitrarily shaped sources, including in particular Gaussians of arbitrary radius.

1+15 pages, 7 figures (24 pdf images)

References in corpus (7)

• On the generalized eigenvalue method for energies and matrix elements in lattice field theory
• Charmonium excited state spectrum in lattice QCD
• Nucleon Structure from Lattice QCD Using a Nearly Physical Pion Mass
• A Stochastic Method for Computing Hadronic Matrix Elements
• Improved interpolating fields for hadrons at non-zero momentum
• Systematic errors in extracting nucleon properties from lattice QCD
• Evolutionary Fitting Methods for the Extraction of Mass Spectra in Lattice Field Theory

Cited by in corpus (7)

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• Nucleon matrix elements from lattice QCD with all-mode-averaging and a domain-decomposed solver: an exploratory study
• Free-form smearing for bottomonium and B meson spectroscopy
• Electromagnetic form factors of the nucleon from $N_f=2+1$ lattice QCD