Infrared features of unquenched finite temperature lattice Landau gauge QCD

Abstract

The color diagonal and color antisymmetric ghost propagators slightly above ${T}_{c}$ of ${N}_{f}=2$ MILC ${24}^{3}\ifmmode\times\else\texttimes\fi{}12$ lattices are measured and compared with zero-temperature unquenched ${N}_{f}=2+1$ ${\mathrm{MILC}}_{c}$ ${20}^{3}\ifmmode\times\else\texttimes\fi{}64$ and ${\mathrm{MILC}}_{f}$ ${28}^{3}\ifmmode\times\else\texttimes\fi{}96$ lattices and zero-temperature quenched ${56}^{4}$ $\ensuremath{\beta}=6.4$ and 6.45 lattices. The expectation value of the color antisymmetric ghost propagator ${\ensuremath{\phi}}^{c}(q)$ is zero, but its Binder cumulant, which is consistent with that of ${N}_{c}^{2}\ensuremath{-}1$ dimensional Gaussian distribution below ${T}_{c}$, decreases above ${T}_{c}$. Although the color diagonal ghost propagator is temperature independent, the ${l}^{1}$ norm of the color antisymmetric ghost propagator is temperature dependent. The expectation value of the ghost condensate observed at zero-temperature unquenched configuration is consistent with 0 in $T>{T}_{c}$. We also measure transverse, magnetic, and electric gluon propagator and extract gluon screening masses. The running coupling measured from the product of the gluon dressing function and the ghost dressing function are almost temperature independent, but the effect of ${A}^{2}$ condensate observed at zero temperature is consistent with 0 in $T>{T}_{c}$. The transverse gluon dressing function at low temperature has a peak in the infrared at low temperature, but it becomes flatter at high temperature. The magnetic gluon propagator at high momentum depends on the temperature. These data imply that the magnetic gluon propagator and the color antisymmetric ghost propagator are affected by the presence of dynamical quarks, and there are strong nonperturbative effects through the temperature-dependent color antisymmetric ghost propagator.