EFFECTIVE-FIELD THEORIES FOR NUCLEI AND DENSE MATTER

A recent development on the working of effective field theories in nuc lei and in dense hadronic matter is discussed. We consider two extreme regimes: One, dilute regime for which fluctuations are made on top of the matter-free vacuum; two, dense systems for which fluctuations are treated on top of the ''vacuum'' defined at a given density, with mas ses and coupling constants varying as function of matter density (''Br own-Rho scaling''). Based on an intricate - as yet mostly conjectural - connection between the in-medium structure of chiral Lagrangian fiel d theory which is a beautiful effective theory of QCD and that of Land au Fermi liquid theory which is an equally beautiful and highly succes sful effective theory of many-body systems, it is suggested that a chi ral Lagrangian with Brown-Rho scaling in the mean field is equivalent to Fermi-liquid fixed point theory. I make this connection using elect roweak and strong responses of nuclear matter up to nuclear matter den sity and then extrapolating to higher densities encountered in heavy-i on collisions and compact stars.