Gauge-invariant quark-antiquark nonlocal condensates in lattice QCD
  We study, by numerical simulations on a lattice, the behaviour of the gauge-invariant quark-antiquark nonlocal condensates in the QCD vacuum with dynamical fermions. A determination is also done in the quenched approximation and the results are compared with the full-QCD case. The fermionic correlation length is extracted and compared with the analogous gluonic quantity. 
M. D'Elia, A. Di Giacomo, E. Meggiolaro