Gauge Fields Condensation at Finite Temperature

Abstract

The two-loop effective action for the SU(3) gauge model in a constant background field ${\bar A}_0(x,t)=B_0^3T_3+B_0^8T_8$ is recalculated for a gauge with an arbitrary $ξ$-parameter. The gauge-invariant thermodynamical potential is found and its extremum points are investigated. Within a two-loop order we find that the stable nontrivial vacuum is completely equivalent to the trivial one but when the high order corrections being taken into account the indifferent equilibrium seems to be broken. Briefly we also discuss the infrared peculiarities and their status for the gauge models with a nonzero condensate.