RUI: Probing Quantum Dynamics in Molecular Magnets and Superconducting Devices

****技术摘要****本项目将探索“宏观”物体的量子动力学特性，即单分子磁体（SMMs）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工原子，能够揭示量子现象，如隧道和叠加态。因此，它们在新兴的量子计算领域有望成为量子比特。在这个项目中，一些新的量子现象将在这些系统中进行研究，潜在地阐明它们作为量子比特的适用性。smm的微波光谱将用于探索“禁止”跃迁，其中自旋隧穿解除了选择规则。由于动态相位干涉效应，这种被禁止的跃迁预计具有非线性的功率依赖性。几何（或Berry）相位干涉将在smm和Josephson器件中进行研究，通过寻找对动态过程（如隧道）的抑制，当干涉是破坏性的。该研究将主要在本科院校进行，本科生学者、研究生、博士后和教职员工将积极参与。这些研究活动将提供充分的培训和指导机会，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。量子比特是量子计算机的处理元素，它既要足够大，能够单独寻址，又要足够小，能够长时间保持定义良好的量子态。该项目将研究占据这一中间地带的人工量子物体（磁性分子和超导装置）的量子特性。微波光谱学将用于探索磁性分子中的“禁止”跃迁，这将阐明它们的量子特性，并可能预示它们作为量子比特的可行性。量子干涉（最违反直觉的量子效应之一，一个物体似乎同时采取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，以揭示在“宏观”物体中观察到这种告密的量子效应的程度。该研究将主要在本科院校进行，本科生学者、研究生、博士后和教职员工将积极参与。这些研究活动将提供充分的培训和指导机会，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.