Müller, B; Rafelski, J, *Temperature dependence of the bag constant and the effective lagrangian for gauge fields at finite temperatures*,
Physics Letters B, vol. 101 no. 1-2
(1981),
pp. 111-118 [doi] .
**Abstract:**

*We calculate the free energy for a gauge field at finite temperature in the presence of a constant gauge magnetic field in the one-loop approximation, omitting unstable modes. The effect of finite temperature on the approximate "true" Savvidy ground state of QCD is derived. A phase transition to the perturbative ground state at Tcr=1.5Bs 1 4 ≈210 MeV is found. © 1981.*