QII-TAQS: Majorana Nanomanipulation for Topological Quantum Computing

马里兰大学、哈佛大学和普渡大学的研究人员团队旨在开发灵活的方法来存储和操纵量子比特（量子位）中的信息，以实现更强大、更高效的量子计算机。研究人员将对一种“拓扑超导体”施加磁场，这种材料中的电子在低温下可以形成不寻常的对。研究人员将利用对磁场的精细控制来产生和交换电流的量子漩涡，称为涡流，其独特的模式和轨迹编码量子信息。该计划的一个重要组成部分将是开发大型经典计算工具来预测单个电子和漩涡的运动，以简化更昂贵的实验操作的效率。这些软件工具将在nanoHUB.org上公开提供，这是一个开放访问的网站，每年有超过140万的访问者。由四名资深研究人员组成的团队将共同指导和教育四名研究生和八名本科生，重点是通过良好的夏季研究项目招收新的物理学学生，并为三所大学之间的合作学生交流提供机会。在过去的十年里，拓扑量子计算已经被世界各地的工业、国家实验室和大学积极地追求。主动策略通常依赖于马约拉纳费米子沿一维纳米线的实现和传输，这对原子精确的界面、超低温和精心调谐的磁场有着苛刻的要求。研究小组将采用一种颠覆性的新方法，使用磁力显微镜尖端来操纵大块拓扑超导体和约瑟夫森结漩涡核心中的马约拉纳费米子，并读取它们的量子态。潜在的优势包括更大的b场和温度范围，对无序的鲁棒性，以及连续的二维空间，可以探索和控制与预定义导线正交的Majorana相互作用。该团队将(a)提出用于编织马约拉纳束缚态超导涡旋核心的设备和读出机制；(b)在这些系统中进行量子输运的原子尺度模拟；(c)利用分子束外延技术合成拓扑超导体Fe(Se,Te)；(d)使用扫描隧道显微镜识别马约拉纳零模式；(e)利用磁力显微镜操纵涡旋并编织其马约拉纳束缚态；(f)制造和读取基于传输的器件，实现原型拓扑量子位。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。

The team of researchers at the University of Maryland, Harvard University, and Purdue University aims to develop flexible methods to store and manipulate information in quantum bits (qubits), to achieve a more robust and efficient quantum computer. The researchers will apply a magnetic field to a "topological superconductor" - a material in which electrons can form unusual pairs at low temperature. The researchers will use fine control of the magnetic field to create and exchange quantum whirls of electrical current, called vortices, whose distinct patterns and trajectories encode quantum information. An important component of this program will be the development of large-scale classical computing tools to predict the motion of individual electrons and vortices, to streamline the efficiency of more costly experimental operations. The software tools will be publicly available at nanoHUB.org, an open-access website that reaches over 1.4 million visitors annually. Collectively, the team of four senior researchers will advise and educate four graduate students and eight undergraduates, with a strong focus on recruiting new students to physics through well-mentored summer research programs, and on providing opportunities for collaborative student exchanges between the three universities.Topological quantum computing has been aggressively pursued by industries, national laboratories, and universities worldwide in the last decade. The active strategy universally relies on the realization and transport of Majorana fermions along 1D nanowires - with demanding requirements for atomically-precise interfaces, ultra-low temperature, and carefully-tuned magnetic field. The team of researchers will pursue a disruptive new approach using a magnetic force microscope tip to manipulate Majorana fermions in the vortex cores of bulk topological superconductors and Josephson junctions, and to read out their quantum state. Potential advantages include larger B-field and temperature range, robustness to disorder, and a continuous two-dimensional space in which to explore and control Majorana interactions, orthogonal to predefined wires. The team will (a) propose devices and readout mechanisms for braiding Majorana bound states superconducting vortex cores; (b) conduct atomic scale simulations of quantum transport in these systems; (c) synthesize the topological superconductor Fe(Se,Te) using molecular beam epitaxy; (d) use scanning tunneling microscopy to identify Majorana zero modes; (e) use magnetic force microscopy to manipulate vortices and braid their Majorana bound states; and (f) fabricate and read transport-based devices to realize prototype topological qubits.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.