3He in Confinement

在非常低的温度下，所有物质都进入了一个只有量子力学才能描述的状态，在这个状态下，物质的状态被称为量子态。其中一些状态允许电子电流在完全无摩擦的情况下流动，在氦液体中，原子可以在不产生任何热量的情况下流动，这些状态被称为超流体。在这个项目中，利用在项目实验室中制备的极小尺寸多孔玻璃，在各向异性约束中设计了氦的轻同位素氦- 3的新型超流体。这些状态的拓扑结构允许存储量子信息，这是量子计算的重要组成部分，有望在计算机技术中掀起一场革命。低温和量子态的拓扑结构都是必不可少的。研究生和本科生以及一些高中生将学习制作多孔玻璃材料所需的专业技术，并使用扫描电子显微镜、低温学和光学方法对其进行表征，以实现项目目标：创建和识别液氦的新拓扑量子态。高质量的样品也提供与美国、法国、日本和英国的其他实验室合作，用于量子流体的一系列研究应用。此外，我们的网站上有一个活跃的基于软件的工具，由研究生开发和维护，使我们研究的超流体的物理性质可以访问。PI继续倡导公众意识到氦是一种宝贵的自然资源，为最近召开的APS、ACS和MRS赞助的氦经济委员会服务，并在国会、国家电视台、科学杂志上露面，并在国际会议和研讨会上应邀发言。技术摘要：本研究生研究项目包括在可能的费米子p波3He超流体流形中寻找具有工程对称性的新量子态。纳米结构环境来自氧化铝膜上密集的小孔隙阵列，用于定义特定的各向异性环境，并冷却到超低温，用于使用超声波和高分辨率核磁共振进行研究。项目的第二部分是使用高孔隙度的二氧化硅气凝胶，这种气凝胶是由控制各向异性制成的。通过这种方法，最近对这些新物质状态的预测得到了验证，特别是手性和非手性对称状态的相互作用。这种超流体的拓扑结构支持马约拉纳激发，马约拉纳激发被认为是量子信息处理的关键组成部分，并且与拓扑超导体有直接联系。该理论的一个核心方面是各向异性环境可以稳定各向异性超流体状态。在超流体3He中已经有迹象表明这与拓扑超导体UPt3的行为相似。在该项目的研究中，利用玻色子超流体4He的单原子层对表面条件进行了控制。此外，声学谐振腔是使用纳米制造设备制造的。该项目支持继续资助实验物理学的研究生教育和本科生研究。

Nontechnical Abstract:At very low temperatures all matter enters a regime described only by quantum mechanics where the states of matter are called quantum states. Some of these states allow electron currents to flow that are completely frictionless and in helium liquids the atoms can flow without generating any heat, and are called superfluids. In this project new classes of the superfluid of the light isotope of helium, helium-three, are engineered in anisotropic confinement using extremely small-scale porous glass prepared in the project laboratory. The topology of these states allows storage of quantum information which is an essential component of the quantum calculations that promise a revolution in computer technology. Both the low temperatures and the topology of the quantum states are essential. Graduate students and undergraduates, as well as some high school students, learn the specialized techniques that are required to make the porous glass materials and characterize them using scanning electron microscopy, cryogenics, and optical methods to achieve the project goals: creating and identifying new topological quantum states of liquid helium. High quality samples are also provided for collaborations with other laboratories in the USA, France, Japan, and the United Kingdom for a range of research applications on quantum fluids. Furthermore, an active software based tool on our website is developed and maintained by graduate students, to make accessible the physical properties of the superfluids we study. The PI continues advocacy for public awareness of helium as a precious natural resource serving on the recently convened APS, ACS, and MRS sponsored Helium Economics Committee, and appearances before congress, on national television, for science magazines, and at invited talks at international conferences and workshops. Technical Abstract:This project for graduate student research includes the search for new quantum states with engineered symmetry among the manifold of possible fermionic p-wave 3He superfluids. Nano-structured environments from dense arrays of small pores in alumina membranes are used to define specific anisotropic environments and cooled to ultra-low temperatures for investigation using ultra-sound and high resolution NMR. A second part of the project is to use high porosity silica aerogel that is fabricated with controlled anisotropy. With this approach the recent predictions for such new states of matter are tested, particularly the interplay of states with chiral and non-chiral symmetry. The topology of such superfluids support Majorana excitations that have been proposed as a key component of quantum information processing and has a direct connection to topological superconductors. A central aspect of the theory is that anisotropic environments can stabilize anisotropic superfluid states. There is already an indication of this in superfluid 3He that parallels the behavior of the topological superconductor UPt3. In the project's research control of the surface conditions are performed using single atom layers of the bosonic superfluid 4He. Additionally, acoustic resonant cavities are produced using nanofabrication facilities. The project supports continuing funding for graduate education and undergraduate research in experimental physics.