Baryonic and mesonic 3-point functions with open spin indices

We have implemented a new way of computing three-point correlation functions. It is based on a factorization of the entire correlation function into two parts which are evaluated with open spin- (and to some extent flavor-) indices. This allows us to estimate the two contributions simultaneously for many different initial and final states and momenta, with little computational overhead. We explain this factorization as well as its efficient implementation in a new library which has been written to provide the necessary functionality on modern parallel architectures and on CPUs, including Intel's Xeon Phi series.Comment: 7 pages, 5 figures, Proceedings of Lattice 201

Baryonic and mesonic 3-point functions with open spin indices

We have implemented a new way of computing three-point correlation functions. It is based on a factorization of the entire correlation function into two parts which are evaluated with open spin-(and to some extent flavor-) indices. This allows us to estimate the two contributions simultaneously for many different initial and final states and momenta, with little computational overhead. We explain this factorization as well as its efficient implementation in a new library which has been written to provide the necessary functionality on modern parallel architectures and on CPUs, including Intel’s Xeon Phi series

Baryonic and mesonic 3-point functions with open spin indices

We have implemented a new way of computing three-point correlation functions. It is based on a factorization of the entire correlation function into two parts which are evaluated with open spin-(and to some extent flavor-) indices. This allows us to estimate the two contributions simultaneously for many different initial and final states and momenta, with little computational overhead. We explain this factorization as well as its efficient implementation in a new library which has been written to provide the necessary functionality on modern parallel architectures and on CPUs, including Intel’s Xeon Phi series

Octet baryon isovector charges from Nf=2+1 lattice QCD

We determine the axial, scalar and tensor isovector charges of the nucleon, sigma and cascade baryons as well as the difference between the up and down quark masses, mu−md. We employ gauge ensembles with Nf=2+1 nonperturbatively improved Wilson fermions at six values of the lattice spacing in the range a≈(0.039–0.098)  fm, generated by the coordinated lattice simulations (CLS) effort. The pion mass Mπ ranges from around 430 MeV down to a near physical value of 130 MeV and the linear spatial lattice extent L varies from 6.5M−1π to 3.0M−1π, where LMπ≥4 for the majority of the ensembles. This allows us to perform a controlled interpolation/extrapolation of the charges to the physical mass point in the infinite volume and continuum limit. Investigating SU(3) flavor symmetry, we find moderate symmetry breaking effects for the axial charges at the physical quark mass point, while no significant effects are found for the other charges within current uncertainties

High-Speed Torus Interconnect Using FPGAs

In this chapter we describe the architecture of a torus interconnect and its implementation on FPGAs, which so far has been used in two different HPC systems. The network design is optimized for applications which benefit from a tightly coupled network and allows to exchange relatively small messages between nearest neighbours at a high rate. Examples for such applications are lattice quantum chromodynamics (LQCD) simulations and fluid dynamics applications using the Lattice Boltzmann method (LBM). We describe the details of the implementation of our torus network architecture for two massively parallel machines, QCD Parallel Computing on Cell (QPACE) and AuroraScience, and present details on the FPGA resource usage. Furthermore, we discuss optimizations which were necessary to fit the design. Finally, we provide an outlook on possible implementation changes when using more recent generations of FPGAs

Lysosomal integral membrane protein-2 as a phospholipid receptor revealed by biophysical and cellular studies

Lysosomal integral membrane protein-2 (LIMP-2) is a glucocerebrosidase receptor, which is linked to kidney failure and other diseases. Here the authors show that LIMP-2 is also a phospholipid receptor and present the lipid-bound structure of the LIMP-2 luminal domain dimer and discuss its lipid trafficking mechanism