Scaling lattice QCD beyond 100 GPUs

Babich, Ronald; Shi, Guosheng; Clark, Michael A.; Brower, Richard C.; Joo, B'lint; Gottlieb, Steven

doi:10.1145/2063384.2063478

Cited by 94 publications

(98 citation statements)

References 23 publications

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“…Specifics of the ensembles and the number of sources used in each ensemble can also be found in Table I. Quark propagators were computed using the multigrid algorithm [36] or using GPUs [37,38] with a tolerance of 10 −12 in double precision. In the measurements performed on the L = 24 and 32 ensembles, the quark propagators, either unsmeared or smeared at the sink using the same parameters as used at the source, provided two sets of correlation functions for each combination of source and sink interpolating fields, labeled as SP and SS, respectively.…”

Section: Methodsmentioning

confidence: 99%

Two nucleon systems atmπ∼450 MeVfrom lattice QCD

Orginos¹,

Parreño²,

Savage³

et al. 2015

Phys. Rev. D

124

137

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Nucleon-nucleon systems are studied with lattice quantum chromodynamics at a pion mass of mπ ∼ 450 MeV in three spatial volumes using n f = 2 + 1 flavors of light quarks. At the quark masses employed in this work, the deuteron binding energy is calculated to be B d = 14.4 +3.2 −2.6 MeV, while the dineutron is bound by Bnn = 12.5 +3.0 −5.0 MeV. Over the range of energies that are studied, the S-wave scattering phase shifts calculated in the 1 S0 and 3 S1-3 D1 channels are found to be similar to those in nature, and indicate repulsive short-range components of the interactions, consistent with phenomenological nucleon-nucleon interactions. In both channels, the phase shifts are determined at three energies that lie within the radius of convergence of the effective range expansion, allowing for constraints to be placed on the inverse scattering lengths and effective ranges. The extracted phase shifts allow for matching to nuclear effective field theories, from which low energy counterterms are extracted and issues of convergence are investigated. As part of the analysis, a detailed investigation of the single hadron sector is performed, enabling a precise determination of the violation of the Gell-Mann-Okubo mass relation.

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Section: Methodsmentioning

confidence: 99%

Two nucleon systems atmπ∼450 MeVfrom lattice QCD

Orginos¹,

Parreño²,

Savage³

et al. 2015

Phys. Rev. D

124

137

View full text Add to dashboard Cite

show abstract

“…The 2 + 1 flavors of dynamical quarks have strange quark mass tuned to approximate the physical strange quark [23,24] and degenerate u, d quarks with mass parameter a t m = −0.0860 corresponding to a pion mass ∼ 236 MeV [25][26][27]. The large volume and time extent, m π L ∼ 4.3, and m π T ∼ 10, ensure that exponentially suppressed polarization and thermal effects will be negligible.…”

Section: Calculating the Finite-volume Spectrummentioning

confidence: 99%

Coupledππ,KK¯scattering inP

et al. 2015

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We determine elastic and coupled-channel amplitudes for isospin-1 meson-meson scattering in P -wave, by calculating correlation functions using lattice QCD with light quark masses such that mπ = 236 MeV in a cubic volume of ∼ (4 fm)3 . Variational analyses of large matrices of correlation functions computed using operator constructions resembling ππ, KK and qq, in several moving frames and several lattice irreducible representations, leads to discrete energy spectra from which scattering amplitudes are extracted. In the elastic ππ scattering region we obtain a detailed energydependence for the phase-shift, corresponding to a ρ resonance, and we extend the analysis into the coupled-channel KK region for the first time, finding a small coupling between the channels.The study of hadron spectroscopy from first principles QCD is entering a new stage of development where the relationship between the discrete spectrum of the theory in a finite-volume and the infinite-volume scattering amplitudes is being practically utilized to study resonances. The tool which allows us access to the spectrum is lattice QCD in which the quark and gluon fields are considered on a finite-grid of points with only systematically improvable approximations being made.Predictably it is the simplest resonant scattering channel which has attracted the greatest initial interest [1][2][3][4][5], that of ππ with isospin=1, in which a low-lying elastic vector resonance called the ρ appears. These works have made use of the formalism relating the discrete spectrum at rest and in moving frames to elastic scattering amplitudes, which has been in place for many years [6][7][8][9][10]. Recently the extension to coupled-channels has been presented [11][12][13][14], and the first lattice QCD study of a coupled-channel system, that of πK, ηK in S, P and Dwaves, has appeared [15,16], showing that the energy dependence and resonant content of the scattering matrix for such a system can be extracted from finite volume spectra.To date virtually all determinations of hadron scattering amplitudes in lattice QCD calculations have worked with artificially heavy u, d quark mass values, a choice which leads to heavier than physical pseudoscalar mesons -this reduces the computational cost, allowing calculations in smaller volumes (where m π L remains large), and pushes up in energy the thresholds for multihadron scattering such as ππππ, for which a finite-volume formalism is not yet in place (but see Refs. [17][18][19][20] The Hadron Spectrum Collaboration previously computed ππ scattering using 391 MeV pions [21,22], extracting detailed spectra of QCD eigenstates from variational analysis of two-point correlation functions computed in several moving frames in three different volumes. By obtaining a significant number of energy levels in the elastic scattering region they were able to map out the energy dependence of the scattering amplitude and show that there is a narrow ρ resonance barely above ππ threshold.In this paper we deliver an extension of the work presen...

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“…Chroma [13] and QUDA [14,15] were used to perform this work on the Lonsdale cluster maintained by the Trinity Centre for High Performance Computing funded through grants from Science Foundation Ireland (SFI), at the SFI/HEA Irish Centre for High-End Computing (ICHEC), and at Jefferson Laboratory under the USQCD Initiative and the LQCD ARRA project. Gauge configurations were generated using resources awarded from the U.…”

Section: Acknowledgementsmentioning

confidence: 99%

Excited spectroscopy of mesons containing charm quarks from lattice QCD

Moir¹

2014

Proceedings of 31st International Symposium on Lattice Field Theory LATTICE 2013 — PoS(LATTICE 2013)

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We present highly excited spectra of charmonium, charm-light and charm-strange mesons using the dynamical anisotropic lattices of the Hadron Spectrum Collaboration. The use of novel techniques has allowed us to extract these spectra with a high degree of statistical precision, while also enabling us to observe states as high as spin-4, states with exotic quantum numbers and candidate gluonic excitations. We discuss the phenomenology of these spectra, and also present preliminary results of Dπ scattering considering only the lowest partial wave in the isospin-3/2 channel.

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Scaling lattice QCD beyond 100 GPUs

Cited by 94 publications

References 23 publications

Two nucleon systems atmπ∼450 MeVfrom lattice QCD

Two nucleon systems atmπ∼450 MeVfrom lattice QCD

Coupledππ,KK¯scattering inP

Excited spectroscopy of mesons containing charm quarks from lattice QCD

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