An update on the BQCD Hybrid Monte Carlo program

Haar, Taylor; Nakamura, Y.; Stüben, H.

doi:10.1051/epjconf/201817514011

Cited by 40 publications

(31 citation statements)

References 8 publications

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“…9, the Q 2 = 0 value for r 3 is 0.06 (2), which compared to other values is compatible with zero. The Q 2 = 0 values for s 1 , s 2 are s 1 = −0.479 (22) and s 2 = −1.643 (44). The ratio is s 2 /s 1 = 3.42, which is in good agreement with the theoretical value for the ratio from eq.…”

Section: Fan Plotssupporting

confidence: 82%

Patterns of flavor symmetry breaking in hadron matrix elements involving u , d , and s quarks

et al. 2019

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By considering a flavour expansion about the SU (3)-flavour symmetric point, we investigate how flavour-blindness constrains octet baryon matrix elements after SU (3) is broken by the mass difference between quarks. Similarly to hadron masses we find the expansions to be constrained along a mass trajectory where the singlet quark mass is held constant, which provides invaluable insight into the mechanism of flavour symmetry breaking and proves beneficial for extrapolations to the physical point. Expansions are given up to third order in the expansion parameters. Considering higher orders would give no further constraints on the expansion parameters. The relation of the expansion coefficients to the quark-line-connected and quark-line disconnected terms in the 3-point correlation functions is also given. As we consider Wilson clover-like fermions, the addition of improvement coefficients is also discussed and shown to be included in the formalism developed here. As an example of the method we investigate this numerically via a lattice calculation of the flavour-conserving matrix elements of the vector first class form factors. Determination ofẐ

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Section: Fan Plotssupporting

confidence: 82%

Patterns of flavor symmetry breaking in hadron matrix elements involving u , d , and s quarks

et al. 2019

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“…The numerical configuration generation (using the BQCD lattice QCD program [21])) and data analysis (using the Chroma software library [22]) was carried out on the IBM BlueGene/Q and HP Tesseract using DIRAC 2 resources (EPCC, Edinburgh, UK), the IBM Blue-Gene/Q (NIC, Jülich, Germany) and the Cray XC40 at HLRN (The North-German Supercomputer Alliance), the NCI National Facility in Canberra, Australia (supported by the Australian Commonwealth Government) and Phoenix (University of Adelaide). ZRK was supported by an Australian Government Research Training Program (RTP) Scholarship.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Electromagnetic contribution to Σ - Λ mixing using lattice QCD+QED

Kordov

Horsley²,

Nakamura

et al. 2020

Phys. Rev. D

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Mixing in the Σ 0 -Λ 0 system is a direct consequence of broken isospin symmetry and is a measure of both isospin-symmetry breaking as well as general SU(3)-flavour symmetry breaking. In this work we present a new scheme for calculating the extent of Σ 0 -Λ 0 mixing using simulations in lattice QCD+QED and perform several extrapolations that compare well with various past determinations. Our scheme allows us to easily contrast the QCD-only mixing case with the full QCD+QED mixing.

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“…The t = 0 entry is plain RHMC, included for reference. .6269 9.02 0.0305 1 26. 12 2.6352 9.12 0.0114 0.74Table B.7: 2tRHMC forces on the 24 3 × 48 lattice.…”

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confidence: 99%

Single flavour optimisations to Hybrid Monte Carlo

Haar

Kamleh

Zanotti

et al. 2019

Computer Physics Communications

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It has become increasingly important to include one or more individual flavours of dynamical fermion in lattice QCD simulations. This is due in part to the advent of QCD+QED calculations, where isospin symmetry breaking means that the up, down, and strange quarks must be treated separately. These single-flavour pseudofermions are typically implemented as rational approximations to the inverse of the fermion matrix, using the technique known as Rational Hybrid Monte Carlo (RHMC). Over the years, a wide range of methods have been developed for accelerating simulations of two degenerate flavours of pseudofermion, while there are comparatively fewer such techniques for single-flavour pseudofermions. Here, we investigate two different filtering methods that can be applied to RHMC for simulating single-flavour pseudofermions, namely polynomial filtering (PF-RHMC), and filtering via truncations of the ordered product (tRHMC). A novel integration step-size tuning technique based on the characteristic scale is also introduced. Studies are performed on two different lattice volumes, demonstrating that one can achieve significant reductions in the computational cost of single-flavour simulations with these filtering techniques.

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An update on the BQCD Hybrid Monte Carlo program

Cited by 40 publications

References 8 publications

Patterns of flavor symmetry breaking in hadron matrix elements involving u , d , and s quarks

Patterns of flavor symmetry breaking in hadron matrix elements involving u , d , and s quarks

Electromagnetic contribution to Σ - Λ mixing using lattice QCD+QED

Single flavour optimisations to Hybrid Monte Carlo

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