n uc l - th / 9 41 20 16 v 1 9 D ec 1 99 4 Instanton content of finite temperature QCD matter

We investigate the temperature dependence of the instanton content of gluon fields and their contribution to quark correlation using quenched lattice QCD and the cooling method. We found a suppression of the topological susceptibility at finite temperature, agreeing with the PCAC expectation at low temperature and enhanced suppression for temperatures at and above the deconfinement transition. For temperatures up to about 334 MeV, the topo-logical charge correlation agrees well with a single instanton profile, though the size parameter seems to change across the phase transition. The screening wave functions for the pion and the rho become slightly more compact at higher temperatures. Lattice cooling shows no contribution from the in-stantons to the screening wave functions at temperatures above the phase transition.