Pomerons and Lattices: a Progress Report

We report on some attempts to use lattice QCD to investigate topics in strong interactions phenomenology which are usually interpreted in terms of soft Pomeron exchange.Comment: Talk presented at LAT96, 3 pages, Latex, one style file and 2 PostScript pictures include

The Gluon Propagator in Momentum Space

We give preliminary numerical results for the gluon propagator evaluated both in coordinate and momentum space on a 16^3X40 quenched lattice at beta=6.0. Our findings are compared with earlier results in the literature at zero momentum. In addition, by considering nonzero momenta we attempt to extract the form of the propagator and compare it to continuum predictions formulated by Gribov and others. latex, file espcrc2.sty needed (appended at the end: search for espcrc2.sty).Comment: 4 page

Search for Lambda^2/p^2 corrections to the QCD running coupling

We investigate the occurrence of power terms $(Lambda^2/p^2$ in the running QCD coupling by analysing non-perturbative measurements of $\alpha_s(p)$ at quite low momenta obtained from the lattice three-gluon vertex. Our study provides some evidence for such a contribution. The phenomenological implications of such a presence are reviewed.Comment: 3 pages, 1 figure, LaTeX, LATTICE98(Confinement

Canonical sampling through velocity-rescaling

We present a new molecular dynamics algorithm for sampling the canonical distribution. In this approach the velocities of all the particles are rescaled by a properly chosen random factor. The algorithm is formally justified and it is shown that, in spite of its stochastic nature, a quantity can still be defined that remains constant during the evolution. In numerical applications this quantity can be used to measure the accuracy of the sampling. We illustrate the properties of this new method on Lennard-Jones and TIP4P water models in the solid and liquid phases. Its performance is excellent and largely independent on the thermostat parameter also with regard to the dynamic properties

Status of alpha_s determinations from the non-perturbatively renormalised three-gluon vertex

We demonstrate the feasibility of computing alpha_s from the lattice three-gluon vertex in the Landau gauge. Data from 16^4 and 24^4 quenched lattices at beta=6.0 are presented. Our main result is that 2-loop asymptotic scaling is observed for momenta in the range 1.8-2.3 Gev, where lattice artifacts appear to be under control.Comment: 3 pages, LaTeX, 2 PostScript pictures and style file included. To appear in the proceedings of LAT9