Anisotropic lattice with nonperturbative accuracy

We determine the nonperturbative anisotropic parameter of the gauge action in the quenched approximation with less than 1% accuracy using the Sommer scale measured by the L\"uscher-Weisz algorithm or smearing technique. We also study the nonperturbative O(a)-improvement of the quark action. The bare quark anisotropy is determined using the masses from the temporal and spatial directions. For the determination of the $O(a)$ improvement coefficients, we apply the Schr\"odinger functional method.Comment: 3 pages, 5 figures, Lattice2004(improved

Wilson and Domainwall Kernels on Oakforest-PACS

We report the performance of Wilson and Domainwall Kernels on a new Intel Xeon Phi Knights Landing based machine named Oakforest-PACS, which is co-hosted by University of Tokyo and Tsukuba University and is currently fastest in Japan. This machine uses Intel Omni-Path for the internode network. We compare performance with several types of implementation including that makes use of the Grid library. The code is incorporated with the code set Bridge++.Comment: 8 pages, 9 figures, Proceedings for the 35th International Symposium on Lattice Field Theory (Lattice 2017

Practical Implementation of Lattice QCD Simulation on Intel Xeon Phi Knights Landing

We investigate implementation of lattice Quantum Chromodynamics (QCD) code on the Intel Xeon Phi Knights Landing (KNL). The most time consuming part of the numerical simulations of lattice QCD is a solver of linear equation for a large sparse matrix that represents the strong interaction among quarks. To establish widely applicable prescriptions, we examine rather general methods for the SIMD architecture of KNL, such as using intrinsics and manual prefetching, to the matrix multiplication and iterative solver algorithms. Based on the performance measured on the Oakforest-PACS system, we discuss the performance tuning on KNL as well as the code design for facilitating such tuning on SIMD architecture and massively parallel machines.Comment: 8 pages, 12 figures. Talk given at LHAM'17 "5th International Workshop on Legacy HPC Application Migration" in CANDAR'17 "The Fifth International Symposium on Computing and Networking" and to appear in the proceeding

Temporal meson correlators at finite temperature on quenched anisotropic lattice

We study charmonium correlators at finite temperature in quenched anisotropic lattice QCD. The smearing technique is applied to enhance the low energy part of the correlator. We use two analysis procedures: the maximum entropy method for extraction of the spectral function without assuming specific form, as an estimate of the shape of spectral function, and the $\chi^2$ fit assuming typical forms as quantitative evaluation of the parameters associated to the forms. We find that at $T\simeq 0.9T_c$ the ground state peak has almost the same mass as at T=0 and almost vanishing width. At $T\simeq 1.1T_c$, our result suggests that the correlator still has nontrivial peak structure at almost the same position as below $T_c$ with finite width.Comment: Lattice 2002 Nonzero temperature 3page

Anisotropic lattices for precision computations in heavy flavor physics

We study the anisotropic lattice QCD for precision computations of heavy-light matrix elements. Our previous study in which the lattices are calibrated with a few percent accuracy has already given results comparable to the existing calculations. This suggests that even higher precision may be achieved by a more precise calibration of anisotropic lattices. We describe our strategy to tune the gauge and quark parameters with accuracies much less than 1 % in the quenched approximation.Comment: 3 papes, 2 figures, Lattice2003(heavy

Precision study of B^* B\pi coupling for the static heavy-light meson

We compute the B^*B\pi coupling \hat{g}_{\infty} for static heavy-light meson using all-to-all propagators. It is shown that low-mode averaging with 100 low-lying eigenmodes indeed improves the signal for the 2-point and 3-point functions for heavy-light meson significantly. Our study suggests that the all-to-all propagator will be a very efficient method for high precision computation of the B^*B\pi coupling especially in unquenched QCD where the number of configurations is limited.Comment: 30 pages, 25 figures, typos correcte

Charmonium near the deconfining transition on the lattice

We study the charmonium properties at finite temperature using quenched lattice QCD simulations. Although a simple potential model analysis indicates no bound state at $T>1.05T_c$, our analyses of the spatial correlation between quark and anti-quark and the spectral function indicate that a bound-state-like structure may survive even above $T_c$.Comment: 4 pages, 3 figures, Talk presented at the PANIC02 conference, Sept. 30 - Oct. 4, 2002, Osaka, Japa