Disorder Induced Novel Quantum Phases in Superfluid 3He

****非技术摘要****无序物理学作为一条共同的主线被整合在一个非常大的科学领域中，对这一主题的研究的影响从高度实用渗透到纯学术。这个项目解决了一个基本问题：？量子物质的本质如何在无序状态下进化？？与其他物理系统不同，3He在低温下的液态是一个独特的，实际上是无无序的系统，我们对它有定量的了解。此外，3He的超流体相，可以更普遍地描述为非常规超导性，已知对外部无序表现出极端敏感性。这个项目将研究受控无序对物质这种独特量子态的影响。研究了两种不同形式的无序：高孔隙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确定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小组进行。本科科研是教育的重要组成部分，也是留住物理专业本科生的有效途径。项目负责人将继续透过讲座/示范及参与科学展览，与本地科学教师和学生互动。****技术摘要****本项目将研究3He在高孔隙率气凝胶和以膜形式限制的可控无序存在下的超流相。提出的项目的最终目标是确定已经预测在这些系统中出现的无序诱导的新量子相。在单轴变形气凝胶中，各向异性失序对各向异性超流体的影响可以进行系统的研究。由于在拉伸气凝胶中引起的各向异性紊乱，预测类一维极性相是稳定的。实验将采用最先进的微机电系统（MEMS）来形成受控薄膜并检测各种相变特征，以阐明表面无序对超流体3He的影响。该项目将专注于准二维薄膜，其中理论上预测了A-B过渡的再入行为和非均匀超流体相的出现。这项研究将由研究生和本科生两个小组进行。留住物理系本科生和增加物理系本科生的数量同样重要。一个有效的方法无疑是通过本科生研究。

****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.