RUI: Macroscopic Quantum Phenomena in Single-Molecule Magnets and Superconducting Devices

Amherst College, Amherst MA

Investigators

Abstract

****NON-TECHNICAL ABSTRACT**** Atoms and elementary particles are decidedly quantum mechanical: these objects can seemingly be in more than one mutually exclusive state at the same time. While such counterintuitive behavior is foreign in most of the everyday world, certain macroscopic systems have been experimentally demonstrated to behave quantum mechanically. Such systems can potentially be exploited as qubits - the elements of quantum computers that process data - and could thereby one day revolutionize computing. This individual investigator award supports a research project that will experimentally elucidate the extent to which chemically synthesized nanomagnets and lithographically fabricated superconducting devices can behave quantum mechanically. New macroscopic quantum phenomena will be explored; the experiments will illuminate how a quantum system's environment can affect its behavior by either suppressing or enhancing telltale quantum phenomena. The results will have implications for the viability of these systems as potential qubits. The research will be conducted primarily at an undergraduate institution and will involve collaborations between undergraduate student-scholars, graduate students, postdoctoral researchers and faculty. Such interactions will not only produce important research results but will also serve to educate and train students pursuing careers in science or related technical fields. ****TECHNICAL ABSTRACT**** This individual investigator award supports a research project that will explore the extent to which macroscopic objects can behave quantum mechanically by looking for new macroscopic quantum phenomena in single-molecule magnets (SMMs) and superconducting devices. Both systems have a collective coordinate (spin orientation for SMMs or phase or charge for superconducting systems) that behaves quantum mechanically. Building on recent work that showed that 10^16 SMM spins can be collectively coupled to a microwave cavity, the project aims to look for related effects, including superradiance, as well as coherent interference effects in which a strong microwave field repeatedly drives the spins through a Landau-Zener transition. In superconducting devices, the project will look for a geometric-phase effect that can suppress tunneling as well as some novel forms of dynamical-phase interference effects. These experiments will illuminate how the system's environment can affect its behavior by either suppressing or enhancing telltale quantum phenomena. The results will have implications for the viability of these systems as potential qubits. The research will be conducted primarily at an undergraduate institution and will involve collaborations between undergraduate student-scholars, graduate students, postdocs and faculty. Such interactions will not only produce important research results but will also serve to educate and train students pursuing careers in science or related technical fields.