This is a collaborative award that supports theoretical research and education in the area of condensed matter theory. The collaborator is professor Kirkpatrick at the University of Maryland (DMR-0132726). The main objective of the project is to enhance the current understanding of many-electron systems at very low temperatures, and especially of phase transitions and other collective phenomena in such systems. The PIs will apply an effective field theory, developed during previous grant periods, to various collective phenomena of electrons in solids. The methods employed are general field theoretic techniques and the renormalization group. Specific systems for which this project is relevant include, magnets, superconductors, and doped semiconductors. The successful completion of this project will contribute to the understanding of an important area of condensed matter physics, and will train technical personnel with theoretical expertise in this field. %%% This is a collaborative award that supports theoretical research and education in the area of condensed matter theory. The collaborator is professor Kirkpatrick at the University of Maryland (DMR-0132726). The research focuses on fundamental problems of condensed matter physics involving strong electronic correlations in clean and disordered systems. Specific topics of study include quantum phase transitions in ferromagnets and superconductors, the coexistence of superconductivity and ferromagnetism in UGe2, and how electronic correlations affect the metal-insulator transition. Quantum phase transitions occur at zero temperature and are driven by quantum fluctuations in contrast to the more familiar and well-understood phase transitions that are driven by thermal fluctuations and have non-zero transition temperatures. Critical fluctuations associated with quantum phase transitions may influence electronic behavior over a wide temperature range and may explain unusual electronic properties exhibited by materials with strong electronic correlations and other condensed matter systems. The award also supports education in advanced theoretical methods for condensed matter phenomena. ***