Quantum Phases in Condensed Matter

Yale University, New Haven CT

Investigators

Abstract

This award supports theoretical research on quantum phase transitions in electronic systems. The PI will extend his previous work to include simultaneously, the effects of interactions between electrons and disorder due to impurities. The main idea is to begin with the Hall problem, where the effects of interactions are well understood and to add on disorder. Evidence that certain magnetic phenomena in a disordered system may be described by an effective pure interaction will be explored. The PI will explore the possibility that a metallic state, disallowed in the noninteracting case, can occur in systems with interactions and disorder. Another focus of this award is on the effective communication of physical concepts and research tools of theoretical condensed matter physics to the community, students, and the lay public. %%% This award supports theoretical research on quantum phase transitions -- transformations that occur at zero temperature through the variation of an interaction or field. These transitions can have a profound effect on materials properties at nonzero temperatures. The PI intends to focus on a notoriously hard problem -- the reliable theoretical description of a disordered and interacting electronic system. The PI will begin from the fractional quantum Hall state in a clean system where the correlations that result from the interactions between electrons are relatively well understood. His strategy will be to introduce disorder and eventually remove the magnetic field in the hope of elucidating the nature of the quantum mechanical ground state of a disordered interacting system in two dimensions. The award will support graduate and postdoctoral training in condensed matter theory and other educational activities, including speaking and writing for a lay audience on condensed matter physics. ***