M. Müller-Preussker

Lattice gluodynamics computation of Landau-gauge Green's functions in the deep infrared

Abstract We present recent results for the Landau-gauge gluon and ghost propagators in SU ( 3 ) lattice gluodynamics obtained on a sequence of lattices with linear extension ranging from L = 64 to L = 96 at β = 5.70 , thus reaching “deep infrared” momenta down to 75 MeV. Our gauge-fixing procedure essentially uses a simulated annealing technique which allows us to reach gauge-functional values closer to the global maxima than standard approaches do. Our results are consistent with the so-called decoupling solutions found for Dyson–Schwinger and functional renormalization group equations.

Dual superconductor scenario of confinement: A Systematic study of Gribov copy effects

We perform a study of the effects from maximal Abelian gauge Gribov copies in the context of the dual superconductor scenario of confinement, on the basis of a novel approach for the estimation of systematic uncertainties from incomplete gauge fixing. We present numerical results, in SU(2) lattice gauge theory, using the overrelaxed simulated annealing gauge-fixing algorithm. We find Abelian and non-Abelian string tensions to differ significantly, their ratio being 0.92(4) at {beta}=2.5115. An approximate factorization of the Abelian potential into monopole and photon contributions has been confirmed, the former giving rise to the Abelian string tension. {copyright} {ital 1996 The American Physical Society.}

Towards the infrared limit in SU(3) Landau gauge lattice gluodynamics

We study the behavior of the gluon and ghost dressing functions in SU(3) Landau gauge at low momenta available on lattice sizes 12{sup 4}-32{sup 4} at {beta}=5.8, 6.0 and 6.2. We demonstrate the ghost dressing function to be systematically dependent on the choice of Gribov copies, while the influence on the gluon dressing function is not resolvable. The running coupling given in terms of these functions is found to be decreasing for momenta q<0.6 GeV. We study also effects of the finite volume and of the lattice discretization.

The Landau gauge gluon and ghost propagators in 4D SU(3) gluodynamics in large lattice volumes

I. L. Bogolubsky a, E.-M. Ilgenfritzb, M. Muller-Preusskerb, and A. Sternbeckc a Joint Institute for Nuclear Research, 141980 Dubna, Russia b Humboldt Universitat zu Berlin, Institut fur Physik, 12489 Berlin, Germany c CSSM, School of Chemistry & Physics, University of Adelaide, SA 5005, Australia E-mail: bogolubs@lxpub04.jinr.ru, ilgenfri@physik.hu-berlin.de, mmp@physik.hu-berlin.de, andre.sternbeck@adelaide.edu.au

Two-color QCD with staggered fermions at finite temperature under the influence of a magnetic field

In this paper we investigate the influence of a constant external magnetic field on the finite-temperature phase structure and the chiral properties of a simplified lattice model for QCD. We assume an SU(2) gauge symmetry and employ dynamical staggered fermions of identical mass without rooting, corresponding to Nf=4 flavors of identical electric charge. For fixed mass (given in lattice units) the critical temperature is seen to rise with the magnetic field strength. For three fixed beta-values, selected such that we stay (i) within the chirally broken phase, (ii) within the transition region or (iii) within the chirally restored phase, we study the approach to the chiral limit for various values of the magnetic field. Within the chirally broken (confinement) phase the chiral condensate is found to increase monotonically with a growing magnetic field strength. In the chiral limit the increase starts linear in agreement with a chiral model studied by Shushpanov and Smilga. Within the chirally restored (deconfinement) phase the chiral condensate tends to zero in the chiral limit, irrespective of the strength of the magnetic field.

Magnetic catalysis (and inverse catalysis) at finite temperature in two-color lattice QCD

Two-color lattice QCD with

SU(2) lattice gluon propagator: Continuum limit, finite-volume effects, and infrared mass scale mIR

{N}_{f}=4

Landau gauge gluon and ghost propagators from lattice QCD

staggered fermion degrees of freedom (no rooting trick is applied) with equal electric charge

Infrared behavior and Gribov ambiguity in SU(2) lattice gauge theory

q

A Numerical reinvestigation of the Aoki phase with N(f) = 2 Wilson fermions at zero temperature

is studied in a homogeneous magnetic background field