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

超流体 3He 的纳米限制、纳米流体、新相及其转变

基本信息

批准号：
1708341
负责人：
Jeevak Parpia
金额：
$ 56.8万
依托单位：
Cornell University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-06-01 至 2021-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1708341&HistoricalAwards=false
关键词：
Nanoconfinement nanofluidics new phases their

项目摘要

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.

非技术摘要研发的速度正在加速。我们的日常设备越来越强大，更便宜，更快。这些消费品中的大多数内置技术都存在，这是由于冷凝物质研究的基本进步。未来的进步将是由于好奇心驱动对新制度的好奇心探索目前仅在实验室环境中可访问的。当该计划中进行的研究将检查超过3毫米的特殊特性3He的特殊特性，而精确定义的结构小于千分之一的高度，这标志着从批量的三维行为到新的二维制度的过渡。本科生和博士学位的学生将设计和制造这些结构，开辟了新的量子纳米流体学区域。表面将必须具有明确的平滑度 - 表面涂层（磁场下纯氦4或氦3）应改变出现的超氟化态（“相位”）的类型。这些阶段应显示“手性”的属性，该属性应该具有像旋转顶部一样的属性。此外，从一个状态到另一种状态（“相位过渡”）的转换应揭示早期宇宙的模型（对于我们对宇宙进化的理解很重要）是否可以在实验室中进行测试。过去的研究生和本科生与该研究小组合作，一直从事学术界，高科技行业和金融部门的生产职业，而计划中的研究将为新一代学生做好挑战的职业准备。系统从近三维材料转换为二维系统的尺寸范围将由新阶段揭示。这些新阶段应该表现出新颖的特征，例如高度传导的“边缘状态”，这些特征在科学上是令人兴奋的，并且将来可能构成了新型的计量和计算设备的基础。技术摘要：Superfluid 3HE可以为研究活动提供信息，这些研究活动扩展了许多物理领域的领域。该项目结合了纳米流体（复杂且精确地制造的腔体，大小调整为超级流体相干长度的尺度）和低温物理学，以暴露新的尺寸效果。实验活性将使用传输（超流体密度和热电导率）以及新型的纳米级超细线探测激发，以充当局部温度计或光谱仪。研究人员预计，这种限制和超流体基础状态之间的平衡可以稳定，即保留（3HE-B）或断裂（3HE-A）时间逆转对称性也将受到约束的影响。通过测量有或没有施加磁场的限制3HE的相图，将绘制出强耦合强度的压力和温度依赖性的细节，以便更可靠地预测在限制下3HE的相位图。限制还将提供研究由于批量/边缘对应而出现的表面/边缘激发的手段。此外，这项研究活动将为“实验室中的宇宙学”提供一个新的例子。对批量批量生产的限制A和B相之间的一阶转变的研究将有可能在早期宇宙的通货膨胀时期提供过程模型。新的几何形状将探索跨多个接口和多个接口的量子传输物理。通过将低温和纳米制造结合起来，研究生和本科生将接触到激动人心的训练场，该训练场已经为科学家准备了学术界和高科技行业的主角。最终，在限制下出现的新超流体可能在量子计算中引起了人们的关注。