Topological Surface States and New Phases in Superfluid 3He

技术摘要这个个人研究项目培养研究生和本科生，他们从事各种量子凝聚相结构的研究，重点是低温下的3He超流体。这一提议的中心部分是描述某些类型的量子态，这些量子态具有拓扑意义，可以在这些超流体的表面找到。这项研究的影响将在广泛的凝聚态物理中感受到，对理解中微子的基本场论也会产生影响，并可能与理解暗物质有关。据预测，在全球各向异性、高度多孔性的二氧化硅气凝胶中将存在新的氦超流相。这些材料将在本科生的帮助下生长，本科生使用光学双折射和小角X射线技术来表征它们。此外，我们的气凝胶将提供给世界各地有特殊要求的六个实验室。共振腔中的高分辨率声学将用于研究超流3He薄样品中的表面量子态，并将搜索破坏的时间反转对称性的直接证据。这种基本的对称性破缺对在其他实验室进行的各种非常规超导材料的研究具有重要意义。非技术摘要这个个人研究人员项目通过他们在实验物理方面的研究来支持研究生和本科生的教育。该项目开发、创造和表征了具有对称性的物质的新量子态，这些对称性可能对我们的社会产生影响，包括高速计算、无摩擦超流体形式的质量传递以及超导电性的应用。将生长和表征高度多孔的凝胶结构，即所谓的气凝胶，以控制吸入其中的氦超流体的量子态。这些高度同质的样本也将被提供给其他六个要求它们的实验室。该项目进行的基础科学研究为学生提供高分辨率声学、核磁共振和低温技术方面的培训，并促进公众和科学界对保护氦这一宝贵自然资源的认识。

Technical AbstractThis individual investigator project trains graduate and undergraduate students who conduct research on the structure of various quantum condensed phases with a focus on 3He superfluids at low temperatures. The central part of this proposal is to characterize certain types of quantum states which have topological significance and can be found at the surface of these superfluids. The impact of the research will be felt over a broad range of condensed matter physics, on field theories basic to the understanding of neutrinos, and may have relevance to the understanding of dark matter. New superfluid phases of helium have been predicted to exist within globally-anisotropic, highly-porous, silica aerogels. These materials will be grown with assistance from undergraduate students who characterize them using optical birefringence, and small angle Xray techniques. Additionally, our aerogels will be provided to a half-dozen laboratories around the world where there have been specific requests. High-resolution acoustics in resonant cavities will be used used to investigate surface quantum states in thin samples of superfluid 3He and a search for direct evidence of broken, time-reversal symmetry will be conducted. This fundamental broken symmetry is of importance to studies on various unconventional superconducting materials conducted in other laboratories.Non-Technical AbstractThis individual investigator project supports graduate and undergraduate education through their research in experimental physics. The project develops, creates, and characterizes new quantum states of matter which exhibit symmetry properties that have the potential for impact on our society, including high speed computation, transfer of mass in the form of frictionless superfluids, as well as applications of superconductivity. Highly porous, gel structures, so-called aerogels, will be grown and characterized in order to control the quantum states of helium superfluids imbibed within. These highly homogeneous samples will also be provided to a half dozen other laboratories that have requested them. The basic scientific research conducted in this project provides student training in high-resolution acoustics, nuclear magnetic resonance, and low temperature techniques and promotes awareness in both public and scientific communities to conserve helium as a valuable natural resource.