Physics of Confined Electrons and Electron Spins on Liquid Helium

****非技术摘要****电子是所有原子的基本组成部分，它们之间相互作用的形式千变万化，这在很大程度上决定了我们在周围世界看到的各种各样的材料特性。这个实验项目旨在更多地了解电子之间相互作用的表现方式。电子的运动和状态是由量子力学控制的，但在特殊情况下，经典牛顿物理学提供了一个很好的近似它们的行为。在一组实验中，少量电子将逐渐被强迫越来越紧密地聚集在一起，以增加量子力学效应的重要性，并了解这如何影响它们的相互作用。除了带负电荷外，每个电子还像一个极弱的条形磁铁。另一组实验将研究当电子聚集在一起时这些“磁矩”是如何相互作用的。这部分项目的一个重要目的是开发一种测量单个电子磁矩方向的方法。展示这种能力是朝着构建使用单个电子的磁矩作为比特的量子计算机迈出的重要一步。该项目将支持一名博士生的教育，以及本科生研究人员的参与，这些研究人员致力于基础物理学及其在新技术机会中的应用之间的边界。这些学生将学习如何使用最先进的现代纳米科学研究工具，这已被证明是学术界和高科技行业职业生涯的优秀培训。****技术摘要****该个人研究者奖支持一个项目，该项目将利用漂浮在超流氦表面的电子来研究电子-电子相互作用中的量子效应以及量子点结构中的自旋弛豫和退相干。亚微米结构（点）将被开发出来，将电子紧密地限制在氦上的小簇中，并且将测量连续添加电子的能量。这些实验将利用在氦表面可靠移动单个电子的最新进展来测量点外的电子，而不是在传感结构扭曲电位的点内。具有两个捕获电子的类似点结构中的总能量将取决于它们的相对自旋，单重态比三重态低。测量可实现的单线态-三重态分裂，并优化结构以进行大分裂。通过对特定自旋态持续的时间尺度的仔细研究，期望能够确定电子自旋弛豫和退相干时间。测量单电子自旋及其退相干的能力是实现电子自旋量子计算机的关键步骤。本研究将由一名博士生和兼职本科生进行。学生将在实验端学习纳米制造、低温技术和高灵敏度测量，以及关于多体量子系统和量子信息的理论。这些需要足智多谋和注重细节的技能已被证明是在学术界和高科技行业从事科学事业的优秀培训。

****NON-TECHNICAL ABSTRACT****Electrons are a fundamental constituent of all atoms, and it is the tremendous variety of forms their interactions can take that is largely responsible for the wide range of material properties we see in the world around us. This experimental project is aimed at understanding more about the ways in which interactions between electrons manifest themselves. The motion and states of the electrons are governed by quantum mechanics, but under special circumstances classical Newtonian physics provides a good approximation to their behavior. In one set of experiments a small number of electrons will gradually be forced closer and closer together to increase the importance of quantum mechanical effects, and to understand how that affects their interactions. In addition to having a negative electric charge, every electron also acts like an extremely weak bar magnet. Another set of experiments will study how these "magnetic moments" interact as the electrons are brought together. An important aim of this part of the project is to develop a way to measure the orientation of the magnetic moment of a single electron. Demonstrating this capability represents an important step towards constructing a quantum computer that uses the magnetic moments of individual electrons as its bits. This project will support the education of a Ph.D. student, together with the participation of undergraduate researchers, working at the boundary between fundamental physics and its applications to new technological opportunities. These students will learn how to use the most advanced tools of modern nanoscience research, which has proven to be excellent training for careers in both academia and high technology industries.****TECHNICAL ABSTRACT****This individual investigator award supports a project that will use electrons floating on the surface of superfluid helium to study the onset of quantum effects in electron-electron interactions and spin relaxation and decoherence in quantum dot structures. Submicron structures (dots) will be developed to tightly confine electrons on the helium in small clusters, and the energy to successively add electrons will be measured. These experiments will take advantage of recent developments in reliably moving individual electrons across the helium surface to measure electrons outside the dot, rather than within the dot where the sensing structures distort the potentials. The total energy in similar dot structures with two trapped electrons will depend upon their relative spins, with singlet states lying lower than triplets. Measurements of the achievable singlet-triplet splitting will be made, and structures optimized for large splitting. By careful study of the time scales over which particular spin states persist it is expected to be able to determine the electron spin relaxation and decoherence times. The ability to measure single electron spins and their decoherence are key steps on the road to implementing an electron spin quantum computer. This research will be performed by a Ph.D. student and part-time undergraduate students. The students will learn nanofabrication, low-temperature techniques, and high-sensitivity measurements on the experimental end, and about the theory of many-body quantum systems and quantum information. These skills, requiring resourcefulness and attention to detail have proven themselves to be excellent training for scientific careers in academia and high technology industries.