3 research outputs found
Positivity violation for the lattice Landau gluon propagator
We present explicit numerical evidence of reflection-positivity violation for
the lattice Landau gluon propagator in three-dimensional pure SU(2) gauge
theory. We use data obtained at very large lattice volumes (V = 80^3, 140^3)
and for three different lattice couplings in the scaling region (beta = 4.2,
5.0, 6.0). In particular, we observe a clear oscillatory pattern in the
real-space propagator C(t). We also verify that the (real-space) data show good
scaling in the range t \in [0,3] fm and can be fitted using a Gribov-like form.
The violation of positivity is in contradiction with a stable-particle
interpretation of the associated field theory and may be viewed as a
manifestation of confinement.Comment: 5 pages, 6 figures; minor modifications in the text and in the
bibliograph
SU(2) Landau gluon propagator on a 140^3 lattice
We present a numerical study of the gluon propagator in lattice Landau gauge
for three-dimensional pure-SU(2) lattice gauge theory at couplings beta = 4.2,
5.0, 6.0 and for lattice volumes V = 40^3, 80^3, 140^3. In the limit of large V
we observe a decreasing gluon propagator for momenta smaller than p_{dec} =
350^{+ 100}_{- 50} MeV. Data are well fitted by Gribov-like formulae and seem
to indicate an infra-red critical exponent kappa slightly above 0.6, in
agreement with recent analytic results.Comment: 5 pages with 2 figures and 3 tables; added a paragraph on
discretization effect