Collaborative Research: 1D Nanoconfined Helium: A Versatile Platform for Exploring Luttinger Liquid Physics

该奖项资助了一项探索一维（1D）系统物理学的合作努力。限制在一维中的普通物质的行为与限制在二维或三维中的完全不同。随着电子器件的特征尺寸不断减小，理解这种行为变得越来越重要。为了探索一维约束的影响，研究小组将使用一个氦原子模型系统，该模型系统被限制在定制材料中，具有只有几个原子宽的纳米通道。该系统提供了一个独特的优势，即粒子的相互作用可以在很大的范围内变化：从弱相互作用（与用于量子计算的捕获原子相关）到强相互作用（如集成电路中的一维电子线路）。中子散射研究可以探测纳米氦的结构和运动，使研究人员能够在一维上测量和发现独特的物理行为。最先进的计算机模拟将用于在实验室进行的同时进行数值实验，为检验理论预测提供机会。该项目还将支持研究生在样品合成和表征以及实验和高性能计算技术方面的广泛跨学科培训。此外，研究人员将开发量子流体和固体的在线课程，填补现有课程的空白，并与广泛的学生群体就基础和技术重要性的主题进行接触。该奖项支持联合实验和理论研究，以氦为模型系统探索一维空间的量子多体物理。一维系统长期以来一直受到关注，因为它们与二维和三维系统有着深刻的区别，它们的性质可以用准粒子来描述。这种准粒子图像在一维中完全分解，其中基本激励是集体的，并由通用的Tomonaga-Luttinger-liquid （TLL）理论描述。研究团队将开发、优化和探索一个新的TLL物理平台。该项目由紧密耦合的实验和量子模拟研究组成：(1)制备预先镀有稀有气体吸附物的有序模板多孔材料作为具有纳米级孔隙的约束平台；(2)对静态相关函数进行弹性中子散射测量；(3)进行非弹性中子散射测量。研究小组的主要重点将放在两个领域，其中理论预测了尚未经过实验验证的新行为：(1)静态相关性，即使没有真正的长程顺序，TLL预测相关性中的代数衰减；(2)预测了与粒子统计量无关的类粒子空穴激励谱的液体动力学激励。从头算模拟与实验散射测量的结合将在实验室中对奇异场论的预测产生明确的证实。这项研究将加深对一个模型的基本理解，这个模型不仅是当前许多领域的核心，而且在纳米电子学、原子电子学、量子传感和量子信息科学中也有技术应用。该项目还将为学生提供广泛的跨学科培训，包括合成和表征、低温技术、x射线和中子散射、使用国家设施以及场论和高性能计算。此外，研究人员将开发量子流体和固体的在线课程，填补现有课程的空白，并与广泛的学生群体就基础和技术重要性的主题进行接触。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL SUMMARYThis award funds a collaborative effort to explore the physics of one-dimensional (1D) systems. Ordinary matter confined in 1D can behave quite differently than in two or three dimensions. Understanding this behavior has become increasingly important as the feature sizes in electronic devices continue to decrease. To explore the effects of confinement in 1D, the research team will use a model system of helium atoms confined in tailored materials with nanometer channels that are only a few atoms wide. This system offers the unique advantage that the interactions of the particles can be varied over a large range: from weak interactions, relevant to trapped atoms used for quantum computing, to strong interactions, as in one-dimensional electronic wires in integrated circuits. Neutron scattering studies which can probe both the structure and motion of the nanoconfined helium will allow the investigators to measure and discover unique physical behavior in one dimension. State-of-the-art computer simulations will be used to perform numerical experiments in tandem with those undertaken in the laboratory, providing an opportunity to test theoretical predictions. This project will also support broad interdisciplinary training of graduate students in sample synthesis and characterization, and in experimental and high-performance computational techniques. In addition, the researchers will develop an online course in Quantum Fluids and Solids, filling an existing curricular gap and engaging with a broad group of students on a topic of fundamental and technological importance.TECHNICAL SUMMARYThis award supports joint experimental and theoretical research to explore quantum many-body physics in one spatial dimension using helium as a model system. One-dimensional systems have been of long-standing interest due to a profound difference from their two- and three-dimensional counterparts, whose properties can be described in terms of quasiparticles. This quasiparticle picture breaks down completely in one dimension where the fundamental excitations are collective and described by the universal Tomonaga-Luttinger-liquid (TLL) theory. The research team will develop, optimize, and explore a novel platform for TLL physics. The project consists of tightly coupled experimental and quantum-simulation research to (1) fabricate ordered templated porous materials preplated with rare-gas adsorbates as a confinement platform exhibiting nanometer-scale pores; (2) Perform elastic neutron scattering measurements of the static correlation function; and (3) Carry out inelastic neutron scattering measurements. The main focus of the research team will be on two areas where theory predicts novel new behavior that has not been verified experimentally: (1) static correlations where TLL predicts an algebraic decay in the correlations even though no true long-range order is possible; and (2) the dynamical excitations of the liquid where a particle-hole-like excitation spectrum is predicted independent of the particle statistics. The integration of ab initio simulations with experimental scattering measurements will yield unambiguous confirmation of exotic field theory predictions in the laboratory.This research will develop a deeper fundamental understanding of a model that is not only central to many areas of current interest, but also has technological applications in nanoelectronics, atomtronics, quantum sensing, and quantum-information science. The project will also provide students with broad interdisciplinary training in synthesis and characterization, low-temperature techniques, x-ray and neutron scattering, use of national facilities, as well as field theory and high-performance computation. In addition, the researchers will develop an online course in Quantum Fluids and Solids, filling an existing curricular gap and engaging with a broad group of students on a topic of fundamental and technological importance.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.