At high temperatures the spatial correlation functions in QCD can be
described in terms of dimensionally reduced effective theory. In
dimensional reduced effective theory we have
massive fermions are already integrated out. Observables which are
dependent on magnetic(
very high temperatures due to matsubara zero modes in the gauge
sector. Spatial Wilson loop (or spatial Wilson line correlator) which
is sensitive to magnetic d.o.f can be calculated in lattice
non-perturbatively. The spatial Wilson loops obey area law at all
temperatures, and this is characterized by the spatial string tension.
We extract the spatial string tension for
action at temperatures
The calculations shows the dimensional reduction picture becomes valid
at
temperature (vacuum) string tension.