Disorder Induced Novel Quantum Phases in Superfluid 3He

*非技术摘要*无序物理作为一条共同的主线被整合在极其广泛的科学领域中，对这一主题的研究影响从高度实用到纯粹的学术。这个项目解决了一个基本问题：量子物质的性质是如何随着无序的变化而演变的？与其他物理系统不同的是，3He在低温下的液态是一个独特的、实际上是无序的系统，我们对此有一个定量的理解。此外，3He的超流相可以更广泛地描述为非常规超导电性，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状态的影响。我们将研究两种不同的无序形式：高孔率气凝胶中的各向异性无序和液体薄膜中的表面无序。该项目的最终目标是识别预测在这些系统中出现的新的、无序诱导的量子相。这项研究将由研究生和本科生两个团队进行。本科生研究是教育的重要组成部分，也是留住物理学本科生的有效途径。该项目的PI将继续通过讲座/示范和参加科学博览会与当地的科学教师和学生互动。*技术摘要*本项目将研究在高孔率气凝胶呈现受控无序和以薄膜形式禁闭的情况下3He的超流相。这项计划的最终目标是确定无序诱导的新量子相，这些相已经被预测出现在这些系统中。系统地研究了各向异性无序对单轴变形气凝胶中各向异性超流体的影响。由于拉伸气凝胶中诱导的各向异性无序，预测类一维极性相将稳定下来。实验将阐明表面无序对超流3He的影响，使用最先进的微电子机械系统(MEMS)来形成可控薄膜并检测各种相变特征。这个项目将专注于准二维薄膜，其中A-B转变的重入行为和非均匀超流体相的出现已经从理论上得到了预测。这项拟议的研究将由研究生和本科生两个团队进行。留住物理本科生和增加他们的数量同样重要。毫无疑问，一种有效的方法是通过本科生研究。

****NON-TECHNICAL ABSTRACT****The physics of disorder is integrated in an extremely large area of science as a common thread, and the impact of research on this subject permeates from the highly practical to the purely academic. This project addresses a fundamental question: ?How does the nature of a quantum matter evolve in response to disorder?? Unlike other physical systems, the liquid state of 3He at low temperatures is a unique, practically disorder free system for which we have a quantitative understanding. Furthermore, the superfluid phases of 3He, which can be characterized more generally as unconventional superconductivity, are known to exhibit extreme sensitivity to external disorder. This project will investigate the effect of controlled disorder on this unique quantum state of matter. The effect of two distinct forms of disorder: anisotropic disorder in high porosity aerogel and surface disorder in thin films of liquid will be studied. The ultimate goal of the project is to identify novel, disorder-induced quantum phases which have been predicted to emerge in these systems. The research will be conducted by two teams of graduate and undergraduate students. Undergraduate research is an important element of education and also an effective way of retaining Physics undergraduate students in this field. The PI of the project will continue to interact with local science teachers and students through lectures/demonstrations and participation in science fairs. ****TECHNICAL ABSTRACT****This project will investigate the superfluid phases of 3He in the presence of controlled disorder presented by high porosity aerogel and by confinement in the form of films. The ultimate goal of the proposed project is to identify disorder-induced novel quantum phases which have been predicted to emerge in these systems. The effect of anisotropic disorder on anisotropic superfluid can be studied in a systematic way in uniaxially deformed aerogel. The 1D-like polar phase is predicted to be stabilized due to anisotropic disorder induced in stretched aerogel. Experiments will be performed to elucidate the effect of surface disorder on superfluid 3He employing state-of-the-art microelectro-mechanical systems (MEMS) to form controlled films and to detect various phase transition features. This project will focus on quasi-two dimensional films where the re-entrant behavior of the A-B transition and the emergence of an inhomogeneous superfluid phase have been theoretically predicted. The proposed research will be conducted by two teams of graduate and undergraduate students. Retaining Physics undergraduate students is as important as increasing their number. One effective way is undoubtedly through undergraduate research.