Effect of Pair-Breaking Scattering by Extended and Anisotropic Objects in Superfluid 3He

*技术摘要*本项目将研究p波超流体3He中空间扩展物体的对破裂散射效应。具体地说，扩展的各向异性断裂对象是浸泡在大块液体中的高孔隙率气凝胶，边界存在于薄膜中。这些系统的物理性质受到由对破裂散射引起的局域准粒子束缚态的强烈影响。这项实验的最终目标是确定这些系统中预计会出现的杂质态和新的量子相的结构。特别是，薄膜的研究将采用一种新的技术，涉及PI‘s小组开发的MEMS器件。将最先进的MEMS技术与基础研究相结合，可能会为新发现和更好的理解开辟一条道路。这项拟议的研究将由研究生和本科生两个团队进行。博士生将接受培训，以获得低温物理、纳米制造技术、器件技术和计算机模拟方面的广泛专业知识。本科生将有现代科学研究的实践经验，重要的是将有机会密切观察从规划到发表的整个研究过程。*非技术摘要*这项拟议的研究解决了一个基本问题：“量子物质的性质是如何随着无序或边界的存在而演变的？”这是一个至关重要的问题，因为混乱无处不在。与其他物理系统不同，低温下的液氦3提供了一个理想的平台，这主要是因为它可以说是我们对其有详细定量了解的最清洁的系统。此外，氦3的超流相可以被描述为更一般的非常规超导体，它对外部无序表现出极高的敏感性。这个项目将研究受控无序对物质这种独特的量子态的影响，这种无序有两种不同的无序形式：高孔隙率气凝胶中的各向异性无序和薄膜中的表面无序。在这项研究中，一种涉及微米级机器的新实验技术，称为MEMS器件，将被用来研究基本性质。这项拟议的实验的最终目标是识别在这些系统中预计会出现的无序诱导的新量子相。这项拟议的研究将由两名博士生与本科生密切合作进行。本科生研究是教育的重要组成部分，也是留住物理本科生的一条非常有效的途径。

****Technical Abstract****This project will investigate the effects of pair-breaking scattering by spatially extended objects in p-wave superfluid 3He. Specifically, the extended anisotropic pair-breaking objects are high porosity aerogel immersed in bulk liquid and the boundaries present in a thin film. The physical properties of these systems are strongly influenced by the localized quasiparticle bound states induced by the pair-breaking scattering. The ultimate goal of the proposed experiment is to identify the structure of the impurity states and novel quantum phases predicted to emerge in these systems. Especially, the study of thin films will employ a novel technique involving MEMS devices developed in the PI's group. Merging state-of-the-art MEMS technology to fundamental research could open a pathway to new discoveries and better understanding. The proposed research will be conducted by two teams of graduate and undergraduate students. The PhD students will be trained to gain a wide range of expertise in low temperature physics, nano-fabrication technique, device technology, and computer simulations. Undergraduate students will have hands-on experience in modern scientific research and importantly will have an opportunity to closely observe the entire process of conducting research from planning to publication.****Non-Technical Abstract****The proposed research addresses a fundamental question: "How does the nature of a quantum matter evolve in response to the presence of disorder or boundaries?" This is an overarching issue because disorder is ubiquitous. Unlike other physical systems, liquid helium three at low temperatures offers an ideal platform for this mainly owing to the fact that it is arguably the cleanest system which we have a detailed quantitative understanding. Furthermore, the superfluid phases of helium three, which can be characterized as more general unconventional superconductor, are known to exhibit extreme sensitivity to external disorder. This project will investigate the effects of controlled disorder on this unique quantum state of matter presented in two distinct forms of disorder: anisotropic disorder in high porosity aerogel and surface disorder in thin films. In this research, a novel experimental technique involving micrometer-scale machines, called MEMS devices, will be employed to investigate the fundamental nature. The ultimate goal of the proposed experiment is to identify disorder induced new quantum phases expected to emerge in these systems. The proposed research will be carried by two PhD students in close collaboration with undergraduate students. Undergraduate research is an important element of education and also a very effective way of retaining Physics undergraduate student in this field.