Optical Conductivity and Correlated Electron Physics

A. J. Millis
Department of Physics
Columbia University
538 W 120 St, NY NY 10027


The uses of optical conductivity in elucidating the physics
of correlated electron systems are outlined. The low energy
version of the f-sum rule is derived and its limitations
are discussed. The importance of the CMR manganites as
a model system is explained. Errors in previous work
of the authors are corrected. Additional applications
to double perovskites and to the c-axis conductivity
of high Tc superconductors and other materials are presented.