APEmille: a parallel processor in the teraflop range

APEmille is a SIMD parallel processor under development at the Italian National Institute for Nuclear Physics (INFN). APEmille is very well suited for Lattice QCD applications, both for its hardware characteristics and for its software and language features. APEmille is an array of custom arithmetic processors arranged on a tridimensional torus. The replicated processor is a pipelined VLIW device performing integer and single/double precision IEEE floating point operations. The processor is optimized for complex computations and has a peak performance of 528Mflop at 66MHz and of 800Mflop at 100MHz. In principle an array of 2048 nodes is able to break the Tflops barrier. A powerful programming language named TAO is provided and is highly optimized for QCD. A C++ compiler is foreseen. Specific data structures, operators and even statements can be defined by the user for each different application. Effort has been made to define the language constructs for QCD.Comment: Talk presented at LATTICE96(machines

Heavy-Light Wavefunctions in Lattice QCD

Using a multistate smearing method, Coulomb gauge wave functions of heavy-light mesons are studied in lattice QCD. Wave functions for the ground state, the first radially excited S-wave state, and the lowest P-wave states of a heavy-light meson are calculated in quenched approximation. The results are found to be in remarkably good agreement with the predictions of a simple relativistic quark model.Comment: Latex file inputs psfig.tex, and espcrc2.sty, 3 figures in uuencoded fil

Genetic diversity of ancient grape cultivars of the Crimea region

A total of 76 accessions of Crimean autochthonous grape cultivars from the collection of the National Institute of Vine and Wine "Magarach" were genotyped using 22 nuclear and 3 chloroplast microsatellite loci (SSR) to characterize their genetic diversity. The total number of alleles was 238, the mean number of alleles per locus was 10.8 and the range of expected heterozygosity was 0.4-0.88. Several synonyms were identified based on the comparison of microsatellite profiles with INRA and EVD databases. Morphological, eno-carpological and eno-chemical characterization of number of cultivars using BBCH scale and OIV descriptors were performed. A short synopsis of the origin and historical development of Crimean autochthonous grape cultivars is presented

Biological phosphorus and nitrogen removal in a full scale sequencing batch reactor treating piggery wastewater

Research activities carried out at ENEA during the last few years allowed the development of a Sequencing Batch Reactor (SBR) that is able to remove biologically organic waste, nitrogen and phosphorus and that was shown to be particularly suited to obtaining low effluent nutrient concentrations even starting from concentrated wastes. Research on optimisation of time cycles and on process modelling, allowed an advanced comprehension of reactor behaviour and the development of a process able to obtain more than 98% removal of nitrogen, phosphorus and COD, and therefore almost capable of matching effluent standards with a sole biological process. On the basis of laboratory results and process modelling, a full scale SBR plant has been designed and realised. This plant, in ten months of operation, is achieving even better results compared to the laboratory ones

The spin content of the proton in quenched QCD

We present preliminary results on the proton spin structure function at zero momentum, in the quenched approximation. Our calculation makes use of a nonperturbative means of determining the multiplicative renormalization of the topological charge density.Comment: REVTEX, 6 pages, 1 PS figure attached. Pisa preprint IFUP-TH-14/9

More about orbitally excited hadrons from lattice QCD

This is a second paper describing the calculation of spectroscopy for orbitally excited states from lattice simulations of Quantum Chromodynamics. New features include higher statistics for P-wave systems and first results for the spectroscopy of D-wave mesons and baryons, for relatively heavy quark masses. We parameterize the Coulomb gauge wave functions for P-wave and D-wave systems and compare them to those of their corresponding S-wave states.Comment: 21 pages plus 14 figs, 3 include

Correlation Functions of Hadron Currents in the QCD Vacuum Calculated in Lattice QCD

Point-to-point vacuum correlation functions for spatially separated hadron currents are calculated in quenched lattice QCD on a $16^3\times 24$ lattice with $6/g^2=5.7$. The lattice data are analyzed in terms of dispersion relations, which enable us to extract physical information from small distances where asymptotic freedom is apparent to large distances where the hadronic resonances dominate. In the pseudoscalar, vector, and axial vector channels where experimental data or phenomenological information are available, semi-quantitative agreement is obtained. In the nucleon and delta channels, where no experimental data exist, our lattice data complement experiments. Comparison with approximations based on sum rules and interacting instantons are made, and technical details of the lattice calculation are described.Comment: 31 pages in REVTeX (with 10 figures to be added using figures command), MIT CTP #214

Tunneling and the Spectrum of the Potts Model

The three-dimensional, three-state Potts model is studied as a paradigm for high temperature quantum chromodynamics. In a high statistics numerical simulation using a Swendson-Wang algorithm, we study cubic lattices of dimension as large as $64^3$ and measure correlation functions on long lattices of dimension $20^2\times 120$ and $30^2\times 120$. These correlations are controlled by the spectrum of the transfer matrix. This spectrum is studied in the vicinity of the phase transition. The analysis classifies the spectral levels according to an underlying $S_3$ symmetry. Near the phase transition the spectrum agrees nicely with a simple four-component hamiltonian model. In the context of this model, we find that low temperature ordered-ordered interfaces nearly always involve a disordered phase intermediate. We present a new spectral method for determining the surface tension between phases.Comment: 26 pages plus 13 Postscript figures (Axis versions also provided), UU-HEP-92/

Gauge Invariant Smearing and Matrix Correlators using Wilson Fermions at beta=6.2

We present an investigation of gauge invariant smearing for Wilson fermions on a $24^3 \times 48$ lattice at $\beta = 6.2$. 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.Comment: at lattice `92. 4 pages latex + 3 postscript figures. Edinburgh preprint: 92/51

Two-point functions for SU(3) Polyakov Loops near T_c

We discuss the behavior of two point functions for Polyakov loops in a SU(3) gauge theory about the critical temperature, T_c. From a Z(3) model, in mean field theory we obtain a prediction for the ratio of masses at T_c, extracted from correlation functions for the imaginary and real parts of the Polyakov loop. This ratio is m_i/m_r = 3 if the potential only includes terms up to quartic order in the Polyakov loop; its value changes as pentic and hexatic interactions become important. The Polyakov Loop Model then predicts how m_i/m_r changes above T_c.Comment: 5 pages, no figures; reference adde