David Henty

A benchmark suite for high performance Java

Increasing interest is being shown in the use of Java for large scale or Grande applications. This new use of Java places specific demands on the Java execution environments that could be tested and compared using a standard benchmark suite. We describe the design and implementation of such a suite, paying particular attention to Java-specific issues. Sample results are presented for a number of implementations of the Java Virtual Machine (JVM). Copyright

Gauge-invariant smearing and matrix correlators using Wilson fermions at beta =6.2.

We present an investigation of gauge-invariant smearing for Wilson fermions in quenched lattice QCD on a

A methodology for benchmarking Java Grande applications

24^3 \times 48

αs from the non-perturbatively renormalised lattice three-gluon vertex

lattice at

Improved lattice spectroscopy of minimal walking technicolor

\beta = 6.2

The Isgur-Wise function from the lattice

. We demonstrate a smearing algorithm that allows a substantial improvement in the determination of the baryon spectrum obtained using propagators smeared at both source and sink, at only a small computational cost. We investigate the matrix of correlators constructed from local and smeared operators, and are able to expose excited states of both the mesons and baryons.

Quenched heavy-light decay constants

Increasing interest is being shown in the use of Java for large scale or Grande applications. This new use of Java places specific demands on the Java execution environments that could be tested and compared using a standard benchmark suite. EPCC has taken a leading role in the Java Grande Forum work to develop a framework and methodology for such a suite. Initial results presented here show interesting differences between JVMs, demonstrating the validity of the approach. Future work will concentrate on parallel benchmarks.

Light hadron spectrum and decay constants in quenched lattice QCD.

We compute the running QCD coupling on the lattice by evaluating two-point and three-point off-shell gluon Greens functions in a fixed gauge and imposing non-perturbatioe renormalisation conditions on them. Our exploratory study is performed in the quenched approximation at β = 6.0 on 164 and 244 lattices. We show that, for momenta in the range 1.8–2.3 GeV, our coupling runs according to the two-loop asymptotic formula, allowing a precise determination of the corresponding Λ parameter. The role of lattice artifacts and finite-volume effects is carefully analysed and these appear to be under control in the momentum range of interest. Our renormalisation procedure corresponds to a momentum subtraction scheme in continuum field theory, and therefore lattice perturbation theory is not needed in order to match our results to the MS scheme, thus eliminating a major source of uncertainty in the determination of αMS Our method can be applied directly to the unquenched case.

Quenched light hadron mass spectrum and decay constants: The effects of O(a) improvement at β = 6.2

We present a numerical study of spectroscopic observables in the SU(2) gauge theory with two adjoint fermions using improved source and sink operators. We compare in detail our improved results with previous determinations of masses that used point sources and sinks and we investigate possible systematic effects in both cases. Such comparison enables us to clearly assess the impact of a short temporal extent on the physical picture, and to investigate some effects due to the finite spatial box. While confirming the IR-conformal behavior of the theory, our investigation shows that in order to make firm quantitative predictions, a better handle on finite size effects is needed.

Quenched hadrons using Wilson and O(a)-improved fermion actions at β=6.2

We calculate the Isgur-Wise function by measuring the elastic scattering amplitude of a D meson in the quenched approximation on a