QII-TAQS: Solid State Integration of Molecular Qubits

量子信息科学有可能彻底改变我们经济的整个部门，从计算到传感，再到通信。这条道路上令人兴奋的早期步骤包括：1)量子比特阵列（“量子位”）的演示，它可以执行计算任务，并且即将展示超越经典计算机的能力；2)纳米级量子传感器的开发，可以测量从电场、磁场到单光子的一切事物；第三，“飞行量子比特”（通过光纤电缆传输的微小光包）的发展，已经使量子加密的实现成为可能，而使用现有技术，量子加密是不可破解的。然而，前景取决于系统的发展，这些系统表现出制造一台好的计算机、传感器等所必需的精确量子特性。几个世纪以来，化学家们一直在设计和合成新分子时操纵原子状态，使分子成为设计定制量子位和量子系统的主要候选者。早期的实验表明，这种方法是有希望的，但挑战在于如何将这些分子从烧杯中取出（可以这么说）并放到芯片上，这样它们就可以与其他支持技术相连接。这个项目的重点是在这些类似设备的环境中研究候选分子，目的是学习分子量子系统的“设计规则”，并设计新的方法来初始化和测量（写入和读取）量子信息。这项工作将在一个合作网络中进行，包括美国和国外的大学科学家，以及与对建立“量子基础设施”感兴趣的工业合作伙伴的密切联系，这将是支持量子信息科学出现所必需的。这种跨学科的环境将为本科生、研究生和博士后研究人员提供发展量子劳动力的独特培训机会。该项目将开发一个将基于分子自旋的量子比特集成到固态架构中的总体框架，利用通过合成控制配体场和电子-核自旋耦合来调节分子系统中的量子态的能力，展示一种独特的方法来生成设计的量子比特。电子和核自旋量子比特已经在分子系统中被证明具有适当的工程配体。这种性能可以与其他基于金刚石NV中心、硅给体和约瑟夫森结的领先量子比特系统相媲美，并且可以通过化学调谐来定制特定应用的相干特性。然而，到目前为止，该领域依赖于解决方案中大集成的测量，排除了对单量子位特性的研究，阻碍了与现有和新兴量子技术的扩展和集成。解决这一挑战需要一个跨学科的项目，利用自旋动力学理论和建模的框架，从化学量子比特的合成到量子相干特性的验证，再到量子相干器件工程的最终目标。该项目将探索量子功能的要求如何与分子设计和合成以及器件设计和制造的相空间相交叉。随着它的成熟，该框架将发展成为基于分子的量子功能器件设计的路线图，这将与量子信息社区广泛相关，并为如何将基于分子的量子器件最有效地集成到更大的量子功能架构中提供指导。本项目由量子飞跃大创意计划、数学与物理科学理事会化学处和国际科学与工程办公室联合资助。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。

Quantum information science has the potential to revolutionize entire sectors of our economy, from computation, to sensing, to communications. Exciting early steps along this path include: i) the demonstration of arrays of quantum bits, "qubits", that can perform computational tasks and are on the verge of demonstrating the ability to outperform classical computers, ii) the development of nanoscale quantum sensors that allow for measurement of everything ranging from electric and magnetic fields to single photons, and iii) the development of "flying qubits" (tiny packets of light that travel through fiber optic cables) that are already enabling the implementation of quantum encryption that is un-hackable using current technology. The promise, however, rests on the development of systems that exhibit the exact quantum properties necessary to make a good computer, sensor, etc. Chemists have been manipulating atomic states for centuries in the design and synthesis of new molecules - making molecules prime candidates for the design of customized qubits and quantum systems. Early experiments have shown that this approach has promise, but the challenge is to get these molecules out of the beaker (so to speak) and onto a chip so that they can be connected to other supporting technologies. This project focuses on studying candidate molecules in these device-like environments, with the goal of learning the "design rules" for molecular quantum systems and designing new approaches to initialize and measure (write and read) quantum information. This work will take place in a collaborative network involving university scientists in the US and abroad as well as close contact with industrial partners interested in building the "quantum infrastructure" that will be necessary to support the emergence of quantum information sciences. This interdisciplinary environment will provide unique training opportunities for undergraduates, graduate students, and postdoctoral researchers in the development of a quantum workforce. This project will develop a general framework for the integration of molecular spin-based qubits into solid state architectures, harnessing the ability to tune quantum states in molecular systems via synthetic control of ligand fields and electron-nuclear spin coupling to demonstrate a unique approach to generating qubits-by-design. Both electron and nuclear spin qubits have been demonstrated in molecular systems with appropriately engineered ligands. This performance is comparable to other leading qubit systems based on diamond NV centers, silicon donors, and Josephson junctions, and enables chemical tuning to tailor the coherence properties for particular applications. However, the field has thus far relied on measurements of large ensembles in solution, precluding the study of single-qubit properties and impeding scaling and integration with existing and emerging quantum technologies. Addressing this challenge requires an interdisciplinary program that exploits a framework of spin-dynamical theory and modeling to bridge from the synthesis of chemical qubits, to the validation of their quantum coherent properties, to the ultimate goal of quantum coherent device engineering. This project will explore how the requirements of quantum functionality intersect with the phase spaces accessible to molecular design and synthesis at one extreme and device design and fabrication at the other. As it matures, this framework will develop into a roadmap for the design of molecule-based quantum-functional devices that will be of broad relevance to the quantum information community and provide guidance as to how molecule-based quantum devices might be most effectively integrated into larger quantum-functional architectures. This project is jointly funded by Quantum Leap Big Idea Program, the Division of Chemistry in the Mathematical and Physical Sciences Directorate, and the Office of International Science and Engineering.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.