XXIIIrd International Symposium on Lattice Field Theory (original) (raw)
Related papers
The gluon propagator in lattice Landau gauge with twisted boundary conditions
2005
We investigate the infrared behaviour of the gluon propagator in Landau gauge on a lattice with twisted boundary conditions. Analytic calculations using Dyson-Schwinger equations, exact renormalization group and stochastic quantization show that the gluon propagator in Landau gauge approaches zero for small momentum. On the other hand lattice calculations and calculations on a four-torus seem to give rise to a non-zero limit. One possible reason for this difference is the existence of zero-momentum fluctuation modes which potentially give a massive contribution to the gluon propagator. Our simulations show that with twisted boundary conditions these zero-momentum modes are suppressed and the gluon propagator becomes smaller than in a periodic ensemble.
Towards the continuum limit of the lattice Landau gauge gluon propagator
AIP Conference Proceedings, 2011
The infrared behaviour of the lattice Landau gauge gluon propagator is discussed, combining results from simulations with different volumes and lattice spacings. In particular, the Cucchieri-Mendes bounds are computed and their implications for D(0) discussed.
The lattice infrared Landau gauge gluon propagator: the infinite volume limit
Proceedings of The XXVII International Symposium on Lattice Field Theory — PoS(LAT2009), 2010
The Landau gauge lattice gluon propagator is discussed for different sets of lattices. Particular attention is given to its infrared properties. Our results show that the lattice propagator can be made compatible with either the decoupling-like or the scaling-like solution of the Dyson-Schwinger equations. Furthermore, the analysis of the Cucchieri-Mendes bounds is performed considering large volume simulations and the Oliveira-Silva ratios are computed. If the first do not give a clear answer about the value of D(0), the second method favors a D(0) = 0. Finally, the SU(3) and SU(2) propagators are compared in the infrared. It comes out that the propagators are different although the infrared exponents seem to be similar. The analysis suggests a scaling behaviour D(0) ∼ N with the gauge group SU(N).
Infrared behavior of the gluon propagator on a large volume lattice
Physical Review D, 2000
The first calculation of the gluon propagator using an O(a 2 ) improved action with the corresponding O(a 2 ) improved Landau gauge fixing condition is presented. The gluon propagator obtained from the improved action and improved Landau gauge condition is compared with earlier unimproved results on similar physical lattice volumes of 3.2 3 × 6.4 fm 4 . We find agreement between the improved propagator calculated on a coarse lattice with lattice spacing a = 0.35 fm and the unimproved propagator calculated on a fine lattice with spacing a = 0.10 fm. This motivates us to calculate the gluon propagator on a coarse large-volume lattice 5.6 3 × 11.2 fm 4 . The infrared behavior of previous studies is confirmed in this work. The gluon propagator is enhanced at intermediate momenta and suppressed at infrared momenta. Therefore the observed infrared suppression of the Landau gauge gluon propagator is not a finite volume effect.
Lattice gauge theory studies of the gluon propagator
The gluon propagator in Landau gauge is calculated in quenched QCD on a large (32 3 × 64) lattice at β = 6.0. In order to assess finite volume and finite lattice spacing artefacts, we also calculate the propagator on a smaller volume for two different values of the lattice spacing. New structure seen in the infrared region survives conservative cuts to the lattice data, and serves to exclude a number of models that have appeared in the literature.
Exploring the infrared Landau gauge propagators using large asymmetric lattices
Proceedings of XXIVth International Symposium on Lattice Field Theory — PoS(LAT2006)
We report on the infrared limit of the quenched lattice Landau gauge gluon and ghost propagators computed from large asymmetric lattices. In particular, the compatibility of the pure power law infrared solutions of the Dyson-Schwinger equations with the lattice data is investigated and the exponent κ is measured. The gluon lattice data favour κ ∼ 0.52, which would imply a vanishing zero momentum gluon propagator. For the subset of lattices where the ghost propagator was computed, the data are not compatible with a pure power law. Our data also show a decreasing running coupling in the infrared region. Furthermore, positivity violation for the gluon propagator is also verified.
Physical Review D, 2008
For the gluon propagator of pure SU (2) lattice gauge theory in the Landau gauge we investigate the effect of Gribov copies and finite-volume effects. Concerning gauge fixing, we enlarge the accessible gauge orbits by adding nonperiodic Z(2) gauge transformations and systematically employ the simulated annealing algorithm. Strategies to keep all Z(2) sectors under control within reasonable CPU time are discussed. We demonstrate that the finite-volume effects in the infrared regime become ameliorated. Reaching a physical volume of about (6.5 fm) 4 , we find that the propagator, calculated with the indicated improvements, becomes flat in the region of smallest momenta. There are first signs in four dimensions of a decrease towards vanishing momentum.
Infrared gluon propagator from lattice QCD: Results from large asymmetric lattices
Physical Review D, 2006
The infrared limit of the lattice Landau gauge gluon propagator is studied. We show that the lattice data is compatible with the pure power law (q 2) 2κ solution of the Dyson-Schwinger equations. Using various lattice volumes, the infinite volume limit for the exponent κ is measured. Although, the results allow κ = 0.498 − 0.525, the lattice data favours κ ∼ 0.52, which would imply a vanishing zero momentum gluon propagator.
Gluon propagator on coarse lattices in Laplacian gauges
Physical Review D, 2002
The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau gauge in the asymptotic limit. Like Landau gauge, it respects Lorentz invariance, but it is free of Gribov copies; the gauge fixing is unambiguous. In this paper we study the infrared behavior of the lattice gluon propagator in Laplacian gauge by using a variety of lattices with spacings