RUI: Probing Quantum Dynamics in Molecular Magnets and Superconducting Devices

*技术摘要*本项目将探索“宏观”物体的量子动力学性质，即单分子磁体(SMM)和约瑟夫森器件。这些系统中的每一个都可以被认为是一个人造原子，能够揭示量子现象，如隧穿和叠加态。因此，在蓬勃发展的量子计算领域，它们作为量子比特很有希望。在这个项目中，将研究这些系统中的一些新的量子现象，潜在地阐明它们作为量子比特的适用性。SMM的微波光谱学将被用来探索“被禁止的”转变，在这种转变中，选择规则被自旋隧道效应解除。这种禁忌跃迁预计将具有非线性功率依赖性，部分原因是动态相位干扰效应。几何(或Berry)位相干涉将在SMM和约瑟夫森器件中通过寻找对动力学过程的抑制来研究，例如当干涉是破坏性的时，例如隧道效应。这项研究将主要在一个本科生机构进行，本科生-学者、研究生、博士后和教职员工积极参与。研究活动将提供充足的培训和指导机会，帮助参与者发展其未来科学和技术职业所需的技术和领导技能。*非技术摘要*量子计算机利用量子力学的反直觉定律，比任何经典计算机都能更有效地解决一些问题。量子计算机的处理元件量子比特需要足够大，可以单独寻址，也需要足够小，能够在很长一段时间内保持定义良好的量子态。这个项目将研究占据这一中间地带的人造量子对象(磁性分子和超导装置)的量子性质。微波光谱学将被用来探索磁性分子中被禁止的跃迁，这将阐明它们的量子性质，并可能预示它们作为量子比特的生存能力。量子干涉(最违反直觉的量子效应之一，即一个物体似乎同时走两条或两条以上相互排斥的路径)将在磁性分子和超导设备中进行探索，以揭示这种具有说服力的量子效应在多大程度上可以在“宏观”物体中观察到。这项研究将主要在一个本科生机构进行，本科生-学者、研究生、博士后和教职员工积极参与。研究活动将提供充足的培训和指导机会，帮助参与者发展其未来科学和技术职业所需的技术和领导技能。

****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. ****Non-Technical Abstract****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.