Nanoconfinement, nanofluidics, new phases and their transitions for superfluid 3He

非技术摘要研究和开发的步伐正在加快。我们的日常设备功能更强大，更便宜，更快。大多数这些消费品的内置技术的存在是因为凝聚态研究的根本进步。未来的进步将发生，因为好奇心驱动的探索新的制度目前只能在实验室环境中访问。在该计划中进行的研究将检查超流3 He的特殊性质，当被限制在精确定义的结构中时，高度小于千分之一毫米，标志着从大体积三维行为到新的二维状态的过渡。本科生和博士生将设计和制造这些结构，开辟量子纳米流体的新领域。 表面必须具有明确的光滑度-表面涂层（在磁场下使用纯氦4或氦3）应该改变出现的超流体状态（“相”）的类型。这些相应该显示出一种“手性”的性质，这种性质应该像一个旋转的陀螺。此外，从一种状态到另一种状态的转换（“相变”）应该揭示早期宇宙的模型（对我们理解宇宙的演化很重要）是否可以在实验室中进行测试。过去的研究生和本科生与这个研究小组的工作已经在学术界，高科技行业和金融部门的生产性职业生涯，计划的研究将准备新一代的学生具有挑战性的职业生涯。系统从近三维材料转变为更二维系统的尺寸范围将通过新的相来揭示。这些新的阶段应该表现出新的特性，如高导电的“边缘状态”，这是科学上的“令人兴奋的”，并可能在未来形成的基础上的新型设备的计量和计算。技术摘要：超流体3 He可以为跨越物理学许多领域的研究活动提供信息。该项目将纳米流体（复杂而精确制造的腔体，其尺寸调整到超流体的相干长度）与低温物理相结合，以揭示新的尺寸效应。实验活动将使用传输（超流密度和热导率）以及新型纳米级超细线作为局部温度计或光谱仪来探测激发。研究人员预计，全新的p波超流态可以通过这种限制来稳定，并且保持（3 He-B）或破坏（3 He-A）时间反演对称性的超流基态之间的平衡也将受到限制的影响。通过测量有和没有施加磁场的约束3 He的相图，强耦合强度的压力和温度依赖性的细节将被绘制出来，允许更可靠的预测约束下的3 He的相图。 约束也将提供一种方法来研究表面/边缘激发出现的结果，散装/边缘对应。此外，这项研究活动将提供一个新的例子，“宇宙学在实验室”。对封闭的A相和B相之间的一阶跃迁的研究，与体核完全不同，将可能提供早期宇宙暴胀时期过程的模型。新的几何结构将探索量子传输在单个和多个接口的物理。通过结合低温和纳米制造，研究生和本科生将接触到令人兴奋的训练场，为科学家在学术界和高科技行业的领导角色做好准备。最终，在约束下出现的新超流体可能会在量子计算中引起兴趣。

Non-Technical AbstractThe pace of research and development is accelerating. Our everyday devices are ever more capable, cheaper, and faster. Most of these consumer items' inbuilt technology exists because of fundamental advances in condensed matter research. Future advances will happen because of curiosity driven exploration of new regimes presently accessible only in a laboratory environment. The research to be conducted in this program will examine the special properties of superfluid 3He when confined in precisely defined structures less than a thousandth of a millimeter tall, marking the transition from bulk three-dimensional behavior to a new two-dimensional regime. Undergraduate students and Ph.D students will design and fabricate these structures opening up a new area of quantum nano-fluidics. The surfaces will have to have a well-defined smoothness - and the surface coating (with pure helium 4 or helium 3 under a magnetic field) should alter the types of superfluid states ("phases") that emerge. These phases should show a property "chirality" that should have properties like a spinning top. Further, the conversion from one state to another ("phase transition") should reveal whether models of the early universe (important for our understanding of the evolution of the universe) can be tested in the laboratory. Past graduate students and undergraduates working with this research group have gone on to productive careers in academia, high-technology industries and the financial sector, and the planned research will prepare a new generation of students for challenging careers. The size range where the system transforms from a nearly three-dimensional material to a more two-dimensional system will be revealed by new phases. These new phases should exhibit novel characteristics such as highly conducting "edge states" that are scientifically "exciting" and that could, in the future form the basis of new types of devices for metrology and computation. Technical abstract:Superfluid 3He can inform research activity that extends across many fields in Physics. The project combines nanofluidics (intricate and precisely fabricated cavities with sizes tuned to the scale of the superfluid's coherence length) with low temperature physics, to expose new size effects. The experimental activity will probe excitations using transport (superfluid density and heat conductivity) as well as a novel nanoscale ultra-fine wire to act as a local thermometer or spectrometer. Researchers expect that entirely new p-wave superfluid states can be stabilized by such confinement and the balance between the superfluid ground state that preserves (3He-B) or breaks (3He-A) time reversal symmetry will also be affected by confinement. By measuring the phase diagram of confined 3He both with and without an applied magnetic field, details of the pressure and temperature dependence of the strong coupling strength will be mapped out allowing for more reliable prediction of the phase diagrams of 3He under confinement. Confinement will also provide the means to study the surface/edge excitations emerging as a result of bulk/edge correspondence. Furthermore this research activity will provide a new example of "cosmology in the laboratory". Studies of the first-order transition between the confined A and B phases, radically different from nucleation in bulk, will potentially provide a model of processes during the inflationary epoch of the early universe. New geometries will explore the physics of quantum transport across single and multiple interfaces. By combining low temperatures and nano fabrication, graduate students and undergraduates will be exposed to the exciting training ground that has prepared scientists for lead roles in academia and high-technology industries. Eventually, the new superfluids that emerge under confinement might be of interest in quantum computation.