SU(2) lattice gluon propagators at finite temperatures in the deep infrared region and Gribov copy effects

Abstract

We study numerically the SU(2) Landau gauge transverse and longitudinal gluon propagators at non-zero temperatures T both in confinement and deconfinement phases. The special attention is paid to the Gribov copy effects in the IR-region. Applying powerful gauge fixing algorithm we find that the Gribov copy effects for the transverse propagator D_T(p) are very strong in the infrared, while the longitudinal propagator D_L(p) shows very weak (if any) Gribov copy dependence. The value D_T(0) tends to decrease with growing lattice size; however, D_T(0) is non-zero in the infinite volume limit, in disagreement with the suggestion made in [1]. We show that in the infrared region D_T(p) is not consistent with the pole-type formula not only in the deconfinement phase but also for T < T_c. We introduce new definition of the magnetic infrared mass scale ('magnetic screening mass') m_M. The electric mass m_E has been determined from the momentum space longitudinal gluon propagator. We study also the (finite) volume and temperature dependence of the propagators as well as discretization errors.