An analytic method of smearing link variables in lattice QCD is proposed and tested. The differentiability of the smearing scheme with respect to the link variables permits the use of modern Monte Carlo updating methods based on molecular dynamics evolution for gauge-field actions constructed using such smeared links. In examining the smeared mean plaquette and the static quark-antiquark potent...

Multigrid (MG) methods for the computation of propagators of staggered fermions in non-Abelian gauge fields are discussed. MG could work in principle in arbitrarily disordered systems. The practical variational MGmethods tested so far with a “Laplacian choice” for the restriction operator are not competitive with the conjugate gradient algorithm on lattices up to 18. Numerical results are prese...

Constraint solving over finite-sized integers involves the definition of propagators able to capture modular (a.k.a. wrap-around) integer computations. In this paper, we propose efficient propagators for a fragment of modular integer constraints including adders, multipliers and comparators. Our approach is based on the original notion of Clockwise Interval for which we define a complete arithm...

Constraints over variable sequences are ubiquitous and many of their propagators have been inspired by dynamic programming (DP). We propose a conceptual framework for designing such propagators: pruning rules, in a functional notation, are refined upon the application of transformation operators to a DP-style formulation of a constraint; a representation of the (tuple) variable domains is picke...

We investigate the infrared behavior of gluon and ghost propagators in Landau-gauge QCD by means of an exact renormalization group equation. We explain how, in general, the infrared momentum structure of Green functions can be extracted within this approach. An optimization procedure is devised to remove residual regulator dependences. In Landau-gauge QCD this framework is used to determine the...