Peng, GX (reprint author), China Ctr Adv Sci & Technol, World Lab, POB 8730, Beijing 100080, Peoples R China.
A new formalism to calculate the in-medium chiral condensate is presented. At lower densities, this approach leads to a linear condensate. If it is compatible with the famous model-independent result, the pion-nucleon sigma term could be six times the average current mass of light quarks. The modification due to QCD-like interactions may, compared with the linear extrapolation, slow the decreasing speed of the condensate with increasing densities. (C) 2002 Published by Elsevier Science B.V.