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。我们的日常设备比以往任何时候都更强大、更便宜、更快。这些消费品中的大多数内置技术的存在都是因为凝聚态研究的根本进步。未来的进展将是因为好奇心驱动的对新制度的探索，目前只有在实验室环境中才能实现。在这个项目中进行的研究将检验超流3He在限制在小于千分之一毫米高的精确定义的结构中时的特殊性质，这标志着从整体三维行为到新的二维区域的转变。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。表面必须具有定义良好的光滑度--表面涂层(在磁场下使用纯氦4或纯氦3)应该改变出现的超流态(相)的类型。这些相应该显示出一种属性“手性”，它应该具有像旋转陀螺一样的属性。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。与这个研究小组合作的过去的研究生和本科生已经在学术界、高科技行业和金融部门从事了富有成效的职业生涯，计划中的研究将为新一代学生为具有挑战性的职业生涯做准备。新的相将揭示系统从接近三维的材料到更二维的系统的尺寸范围。这些新的相应该表现出新的特征，例如在科学上是“令人兴奋的”的高导电性“边缘状态”，这可能在未来形成用于计量和计算的新型设备的基础。技术摘要：超流体3他可以为跨越物理学多个领域的研究活动提供信息。该项目将纳米流体(复杂而精确制造的空腔，其大小可根据超流体的相干长度调整)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(超流密度和导热系数)以及一种新的纳米级超细金属丝作为局部温度计或光谱仪来探测激发。研究人员预计，这种限制可以稳定全新的p波超流态，保持(3He-B)或破坏(3He-A)时间反转对称性的超流基态之间的平衡也将受到限制的影响。通过测量有无外加磁场的受限~3He相图，可以得到强耦合强度随压力和温度变化的细节，从而可以更可靠地预测~3He在约束下的相图。禁闭还将提供研究由于体/边对应而出现的表面/边激发的手段。此外，这项研究活动还将为“实验室中的宇宙学”提供一个新的范例。对受限的A相和B相之间的一级转变的研究，与整体成核完全不同，可能会提供一个早期宇宙膨胀时期的过程模型。新的几何学将探索单界面和多界面之间的量子传输物理。通过将低温和纳米制造相结合，研究生和本科生将接触到令人兴奋的培训场地，为科学家在学术界和高科技行业担任领导角色做好准备。最终，在禁闭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.