Quantum Mechanics of Macroscopic Variables

9876874 Han将进行实验以探索宏观变量的量子力学性质-在这种情况下，磁通量F连接SQUID（包含约瑟夫森结的超导回路）。这项工作的一个特别的重点将是了解环境（阻尼和温度）的影响F从纯粹的经典量子行为的演变，在两个磁通量威尔斯之间的SQUID开关通过隧穿势垒。系统能量可以被量化为这些宏观上不同的磁通量威尔斯阱中的每一个内的离散能级。在隧穿过程中，系统的磁矩翻转，变化约1010 mB -一个非常宏观的量。因此，这些实验将代表著名的薛定谔猫悖论的物理实现，该悖论是由宏观上不同状态的相干叠加引起的。此外，实验将允许对量子系统与其环境相互作用的基础理论进行受控测试，这适用于许多物理系统：微观和宏观。这项工作将作为纽约州立大学斯托尼布鲁克和堪萨斯大学之间的耦合研究项目进行。最初，在堪萨斯的工作将集中在开发用于测量拉比振荡的新微波技术，而在斯托尼布鲁克的工作将集中在扩展先前技术以及新样本制造上。数据和分析将在组之间共享。%将进行实验来探索宏观变量的量子力学性质-在这种情况下，磁通量F连接超导回路。这项工作的一个特别的重点将是理解与周围物质的相互作用对F从纯经典到量子行为的演变的影响，如在由于量子力学隧穿而引起的环的磁矩的切换中所见。在隧穿过程中，系统的磁矩翻转，变化大约是单个电子的一百亿倍--这是一个非常宏观的量。通量的相干振荡将证明纯粹的量子行为。此外，实验将允许对量子系统与其环境相互作用的基础理论进行受控测试，这适用于许多物理系统：微观和宏观。这项工作将作为纽约州立大学斯托尼布鲁克和堪萨斯大学之间的耦合研究项目进行。最初，在堪萨斯的工作将侧重于发展新的微波技术，用于测量振荡，在斯托尼布鲁克的工作将侧重于扩展以前的技术以及新的样品制造。数据和分析将在各组之间共享。学生将接受基础物理和各种最先进技术（如电子测量和样品制造）的广泛培训，这将为他们的学术和工业生涯做好准备。

9876874HanExperiments will be undertaken to explore the quantum mechanical nature of a macroscopic variable -- in this case the magnetic flux F linking a SQUID (a superconducting loop containing a Josephson junction). A particular focus of this work will be to understand the effects of the environment (damping and temperature) on the evolution of F from purely classical to quantum behavior as seen in the switching of the SQUID between two fluxoid wells by tunneling through a potential barrier. The system energy can be quantized into discrete levels within each of these macroscopically distinct fluxoid wells. During tunneling, the magnetic moment of the system flips, changing by about 1010 mB --- a very macroscopic quantity. Thus these experiments will represent a physical realization of the famous Schrodinger's cat paradox resulting from the coherent superposition of macroscopically distinct states. Additionally, the experiments will permit controlled tests of the underlying theory for the interaction of quantum systems with their environment, which is applicable to many physical systems: microscopic as well as macroscopic. This work will be carried out as coupled research projects between SUNY Stony Brook and the University of Kansas. Initially, work at Kansas will focus on development of new microwave techniques for measurement of Rabi oscillations and at Stony Brook on the extension of previous techniques as well as new sample fabrication. Data and analysis will be shared between groups.%%%Experiments will be undertaken to explore the quantum mechanical nature of a macroscopic variable -- in this case the magnetic flux F linking a superconducting loop. A particular focus of this work will be to understand the effects of interactions with surrounding matter on the evolution of F from purely classical to quantum behavior as seen in the switching of the magnetic moment of the loop due to quantum mechanical tunneling. During tunneling, the magnetic moment of the system flips, changing by about ten billion times that of a single electron --- a very macroscopic quantity. Coherent oscillations of the flux will demonstrate purely quantum behavior. Additionally, the experiments will permit controlled tests of the underlying theory for the interaction of quantum systems with their environment, which is applicable to many physical systems: microscopic as well as macroscopic. This work will be carried out as coupled research projects between SUNY Stony Brook and the University of Kansas. Initially, work at Kansas will focus on development of new microwave techniques for measurement of oscillations and at Stony Brook on the extension of previous techniques as well as new sample fabrication. Data and analysis will be shared between groups. Students will receive extensive training both in fundamental physics and a variety of state-of-the-art techniques such as electronic measurements and sample fabrication, which will prepare them for both academic and industrial careers.