O ct 2 00 1 Extended Brinkman - Rice Picture and Its Application to High - T c Superconductors ∗ Hyun - Tak

This is a full-paper of the paper(Physica C341-348, 259(2000)) published previously. The effective charge and Coulomb energy are justified by means of measurement. Theoretical calculations of the effective mass depending on band filling also are given by Gutzwiller's variational calculations. On the basis of the concept of measurement, the effective mass is an average of the true effective mass in the Brinkman-Rice(BR) picture for metal phase and is the effect of measurement. The true correlation strength (U/U c = κ BR) in the BR picture is evaluated as 0.92< κ BR <1 for YBCO. High-T c super-conductivity is attributed to the true effective mass (regarded as the density of states) caused by the large κ BR value. Furthermore, the validity of the BR picture is indirectly proved through the extended BR picture.