The Determination of the Quark-Gluon Mixed Condensateg<\barqσµνGµνq> from Lattice QCD

We study the quark-gluon mixed condensate g<\bar{q} sigma G q>, using theSU(3)c lattice QCD with the Kogut-Susskind fermion at the quenched level. Wegenerate 100 gauge configurations on the 16^4 lattice with \beta = 6.0, andperform the measurement of the mixed condensate at 16 points in each gaugeconfiguration for each current quark mass of m_q=21, 36, 52 MeV. Using the 1600data for each m_q, we find the ratio between the mixed condensate and the quarkcondensate, m_0^2 = g<\bar{q} sigma G q> / <\bar{q}q> \simeq 2.5 GeV^2 at thelattice scale of 1/a \simeq 2 GeV in the chiral limit. The large value of themixed condensate suggests its importance in the operator product expansions inQCD. We study also chiral restoration at finite temperature in terms of themixed condensate, which is another chiral order parameter. We present thelattice QCD results of the mixed condensate at finite temperature.Comment: 5 pages, Talk given at Tokyo-Adelaide Joint Workshop on Quarks, Astrophysics and Space physics, Tokyo, Japan, Jan.6 - Jan.10, 200