Temperature dependence of electric and magnetic gluon condensates

The contribution of Lorentz nonscalar operators to finite temperature correlation functions is discussed. Using the local duality approach for the one-pion matrix element of a product of two vector currents, the temperature dependence of the average gluonic stress tensor is estimated in the chiral limit to be E2+B2T=(π210)bT4. At a normalization point μ=0.5 GeV we obtain b1.1. Together with the known temperature dependence of the Lorentz scalar gluon condensate we are able to infer E2T and B2T separately in the low-temperature hadronic phase.