Hunting Medium Modifications of the Chiral Condensate
  With QCD sum rule evaluations, spectral changes of hadrons inside nuclear matter are considered, which shed light on QCD condensates and thus on the non-perturbative structure of the QCD ground state. For some light quark configurations, omega meson and nucleon, the relevance of four-quark condensates is compared; the D meson as a representative of heavy-light quark systems is also briefly discussed. 
R. Thomas, S. Zschocke, T. Hilger, B. Kampfer