****Technical Abstract**** This project will explore the quantum dynamical properties of "macroscopic" objects, namely, single-molecule magnets (SMMs) and Josephson devices. Each of these systems can be thought of as an artificial atom capable of telltale quantum phenomena such as tunneling and superposition states. As such, they hold promise as qubits in the burgeoning field of quantum computing. In this project, some novel quantum phenomena will be investigated in these systems, potentially illuminating their suitability as qubits. Microwave spectroscopy of SMMs will be used to explore "forbidden" transitions in which a selection rule is lifted by spin tunneling. Such forbidden transitions are expected to have non-linear power dependence due, in part, to dynamical phase interference effects. Geometric (or Berry) phase interference will be investigated in both SMMs and Josephson devices by looking for the suppression of dynamical processes, such as tunneling, when the interference is destructive. The research will be conducted primarily at an undergraduate institution with active participation of undergraduate student-scholars, a graduate student, a postdoc and a faculty member. The research activities will afford amply opportunities for training and mentoring that will help the participants develop the technical and leadership skills needed in their future scientific and technical careers.
Quantum computers harness the counterintuitive laws of quantum mechanics to solve some problems more efficiently than any classical computer could. Qubits, the processing elements of quantum computers, need to be large enough to be individually addressable yet small enough to be able to maintain well defined quantum states for long periods of time. This project will investigate the quantum properties of artificial quantum objects (magnetic molecules and superconducting devices) that occupy this middle ground. Microwave spectroscopy will be used to explore "forbidden" transitions in magnetic molecules that will illuminate their quantum properties and may herald their viability as qubits. Quantum interference (one of the most counterintuitive of quantum effects in which an object seems to take two or more mutually exclusive paths simultaneously) will be explored in both magnetic molecules and superconducting devices to reveal the extent to which such a telltale quantum effect can be observed in "macroscopic" objects. The research will be conducted primarily at an undergraduate institution with active participation of undergraduate student-scholars, a graduate student, a postdoc and a faculty member. The research activities will afford amply opportunities for training and mentoring that will help the participants develop the technical and leadership skills needed in their future scientific and technical careers.
