 Collective quantum phenomena in highly correlated electronic materials are studied by spectroscopic and scattering techniques.Topics of particular current interest include the interplay between charge, orbital, and spin degrees of freedom in transition metal oxides, the mechanism of high-temperature superconductivity, and the control of electronic phase behavior in metal-oxide superlattices.The department also develops new spectroscopic methods such as high-resolution neutron spectroscopy and spectral ellipsometry.