9706788 Vignale This grant will support the work of a mid-career PI on some fundamental aspects of time dependent density functional theory. The PI has pioneered the generalized current- density functional theory to describe the high frequency effects under weak perturbing potentials. The generalized theory has the prospect of a unified treatment of a large class of phenomena ranging from standard linear response and transport to nonlinear and nonperturbative phenomena and parametric instabilities. The PI will study exact solutions as benchmarks, to learn about the rigorous structure of the exact exchange correlation potentials. The theory will also be generalized to include the electronic spin degree of freedom. The theoretical work will benefit from experiments on the dispersion and lifetime of collective excitations in metals and also on excitations in digitally designed quantum wells. In addition the PI is also planning to investigate the excitations at the edges of quantum Hall systems. %%% This mid-career PI was a pioneer in the development of a theoretical formalism to study the time dependent properties of electrons in metals. This work is widely known as the current-density functional theory. In the present grant, he is planning to develop a unified treatment of the response of atoms, molecules and metals to intense and high frequency electromagnetic fields. The specific effects include a study of nonlinear phenomena and also parametric instabilities in metals and in digitally designed quantum wells. He is also planning to study the special properties of electrons at high fields, the features associated with the edge states in a quantum Hall effect. ***
