We argue that all evidences point towards a finite non-vanishing zero momentum renormalised lattice gluon propagator in the infinite volume limit. We argue that different simulations with different lattice setups end-up with fairly compatible results for the gluon propagator at zero momentum, with different positive slopes as a function of the inverse volume.
We investigate the propagators of 4D SU(2) gauge theory in Landau gauge by Monte Carlo simulations. To be able to compare with perturbative calculations we use large $beta$ values. There the breaking of the Z(2) symmetry causes large effects for all four lattice directions and doing the analysis in the appropriate state gets important. We find that the gluon propagator in the weak-coupling limit is strongly affected by zero-momentum modes.
We consider the interquark potential in the one-gluon-exchange (OGE) approximation, using a fully nonperturbative gluon propagator from large-volume lattice simulations. The resulting VLGP potential is non-confining, showing that the OGE approximation is not sufficient to describe the infrared sector of QCD. Nevertheless, it represents an improvement over the perturbative (Coulomb-like) potential, since it allows the description of a few low-lying bound states of charmonium and bottomonium. In order to achieve a better description of these spectra, we add to VLGP a linearly growing term. The obtained results are comparable to the corresponding ones in the Cornell-potential case. As a byproduct of our study, we estimate the interquark distance for the considered charmonium and bottomonium states.
We investigate propagators in Lorentz (or Landau) gauge by Monte Carlo simulations. In order to be able to compare with perturbative calculations we use large $beta$ values. There the breaking of the Z(2) symmetry turns out to be important for all of the four lattice directions. Therefore we make sure that the analysis is performed in the correct state. We discus implications of the gauge fixing mechanism and point out the form of the weak-coupling behavior to be expected in the presence of zero-momentum modes. Our numerical result is that the gluon propagator in the weak-coupling limit is strongly affected by zero-momentum modes. This is corroborated in detail by our quantitative comparison with analytical calculations.
We calculate loop contributions up to four loops to the Landau gauge gluon propagator in numerical stochastic perturbation theory. For different lattice volumes we carefully extrapolate the Euler time step to zero for the Langevin dynamics derived from the Wilson action. The one-loop result for the gluon propagator is compared to the infinite volume limit of standard lattice perturbation theory.
We study the SU(3) gluon propagator in renormalizable $R_xi$ gauges implemented on a symmetric lattice with a total volume of (3.25 fm)$^4$ for values of the guage fixing parameter up to $xi=0.5$. As expected, the longitudinal gluon dressing function stays constant at its tree-level value $xi$. Similar to the Landau gauge, the transverse $R_xi$ gauge gluon propagator saturates at a non-vanishing value in the deep infrared for all values of $xi$ studied. We compare with very recent continuum studies and perform a simple analysis of the found saturation with a dynamically generated effective gluon mass.