QII-TAQS: Characterizing and Utilizing 2D van der Wals Materials with Superconducting Qubits

量子信息技术有望给传感、通信和计算带来革命性的变化。要实现这一承诺，就需要新的方法来创造“量子就绪”的材料和制造工艺。该项目的研究部分将一种名为“范德华异质结构”的新材料引入制造用于量子计算的高质量器件。范德华异质结构是一类分层的二维(扁平)材料，根据其设计，可能具有广泛的性质，例如像铜这样的普通金属，像铝这样的超导体，或者像氧化铝这样的绝缘体。这些材料的优点是它们是结晶的，因此几乎没有缺陷(如果有的话)。这些异质结构原子锐利的界面也为制造新型电子器件提供了材料平台。缺陷限制了当今量子器件的实用，这项研究的目的是通过利用它们的结晶度来提高量子器件的性能。这项研究包括表征范德华异质结构的电学和光学性质，以及将其用于制造和测试一系列用于量子信息处理的量子器件。该项目还有助于培训新一代“量子工程师”，他们将把这项工作转化为工业环境。调查人员致力于指导和培训本科生、研究生和博士后助理--下一代科学和工程领导者--以及接触那些已经在工作的人和其他公众成员。该项目致力于范德华(VDW)异质结构的表征及其在量子信息技术中的应用。VDW异质结构是一类层状、结晶的二维(2D)量子材料，包括半金属、绝缘体、半导体、铁磁体、超导体和拓扑绝缘体。虽然VDW材料通过直流输运得到了广泛的研究，但很少有实验探索它们在与量子技术应用相关的微波和光学区域的量子性质。在这项工作中，研究小组使用跨越微波、太赫兹和光学频率的相干光学技术来研究2D VDW材料，包括直接激发和使用超导谐振器的电路量子电动力学来调解快速、超灵敏的泵浦-探测实验和检测。该团队汇集了VDW材料、高品质因数超导谐振器、高相干超导量子比特以及它们与VDW异质结构的集成方面的互补专业知识。这些设备的制造利用了内部开发的独特的、最先进的密封设备铸造厂，以及最先进的超导谐振器和量子比特制造。测量在毫克尔文温度下进行，在带有微波和光学通道的无制冷剂稀释冰箱中进行。这项研究的目标是变革性的量子信息应用，包括高相干量子比特、小形状因子微波组件和量子自旋模型的研究。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Quantum information technologies hold the promise to revolutionize sensing, communication, and computing. Realizing this promise requires new approaches for creating "quantum-ready" materials and manufacturing processes. The research part of this project introduces a new class of materials called "van der Waals heterostructures" to the manufacturing of high-quality devices for application to quantum computation. Van der Waals heterostructures are a family of layered, two-dimensional (flat) materials that - depending on their design - may assume a wide range of properties, such as being a normal metal like copper, a superconductor like aluminum, or an insulator like aluminum oxide. The advantage of these materials is that they are crystalline and, therefore, have few (if any) defects. The atomically sharp interfaces of these heterostructures also provide a materials platform to build novel electronic devices. Defects limit the utility of today's quantum devices, and this research aims to improve quantum device performance by leveraging their crystallinity. The research includes characterization of the electrical and optical properties of van der Waals heterostructures, as well as their use to manufacture and test a range of quantum devices useful for quantum information processing. The project also contributes to the training of a new generation of "quantum engineers" who will translate this work into industrial settings. The investigators are committed to the mentoring and training of undergraduates, graduate students, and postdoctoral associates - the next generation of science and engineering leaders - as well as outreach to those already in the workforce and other members of the public. This project addresses the characterization of van der Waals (vdW) heterostructures - a family of layered, crystalline, two-dimensional (2D) quantum materials including semi-metals, insulators, semiconductors, ferromagnets, superconductors, and topological insulators - and their application to quantum information technologies. While vdW materials have been extensively studied via DC transport, few experiments have probed their quantum properties in the microwave and optical regimes relevant for quantum technology applications. In this work, the research team investigates 2D vdW materials using coherent optical techniques spanning microwaves, terahertz, and optical frequencies, including direct excitation and the use of circuit quantum electrodynamics with superconducting resonators to mediate fast, ultra-sensitive pump-probe experiments and detection. The team aggregates complementary expertise in vdW materials, high-quality-factor superconducting resonators, high coherence superconducting qubits, and their integration with vdW heterostructures. Fabrication of these devices leverages a unique, state-of-the-art hermetic device foundry developed in-house, as well as state of-the-art superconducting resonator and qubit fabrication. Measurements are performed at millikelvin temperature in cryogen-free dilution refrigerators with microwave and optical access. The research targets transformative quantum information applications, including high-coherence qubits, small-form-factor microwave components, and the study of quantum spin models.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.