CAREER: Characterization of quantum dot qubits by scannable mechanical resonator

非技术摘要：为了加快量子技术在量子计算等新应用领域的实现，认真研究可以用作量子比特的新型材料至关重要。这个CAREER项目采用实验技术来研究各种纳米级材料，如纳米颗粒、纳米线和分子，以用于在个体水平上制造量子比特。本研究采用扫描探针显微镜技术，利用机械谐振器来检测这些材料中单个电子的运动。该项目为研究量子比特等纳米材料的新方法奠定了基础。研究活动与教育活动紧密结合，包括：1)培训德克萨斯州立大学和合作大学的研究生和本科生应用最先进的基于扫描探针显微镜的测量技术进行材料表征，并创建一个研究人员网络；2)通过研讨会和实践活动，吸引包括初中和高中在内的不同层次的学生参与纳米和量子科学。技术摘要：本CAREER项目旨在研究如何利用机械谐振器来表征双量子点中实现的量子比特的隧道耦合、弛豫和相干等量子力学特性，采用基于原子力显微镜的机械电荷传感技术。可扫描探针的使用使得通过将探针定位在目标量子点上方来表征双量子点成为可能，而不需要在附近集成谐振器或传感电极。该项目的成果将扩大对基于双量子点的机械谐振器和量子比特之间耦合的基本理解，并将为研究广泛的纳米材料开辟道路-纳米颗粒复合物，纳米线，自组装量子点和工程分子-尚未作为量子比特进行研究。这些量子位可以在更高的温度下工作，因为它们具有更高的约束能量，从而使量子技术的应用范围更广。该项目将支持培养先进低温扫描探针显微镜仪器和纳米制造的研究生和本科生。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。

Non-technical abstract:In order to speed up the realization of the quantum technology for novel applications such as quantum computing, it is critical to carefully study new types of materials that can be used as quantum bits. This CAREER project pursues experimental techniques to study diverse nanometer-scale materials such as nanoparticles, nanowires and molecules for their potential use in making quantum bits at their individual level. The research adopts a scanning probe microscopy technique which employs a mechanical resonator to detect the motion of a single electron in these materials. The project lays the foundation of a new way of studying nanomaterials as quantum bits. The research activities are closely integrated with educational activities that include: 1) training graduate and undergraduate students at Texas State University and collaborating universities in applying state­-of-the art scanning probe microscopy based measurement techniques for material characterization and create a network of researchers, and 2) engaging a diverse student body at various levels including middle and high school in nano- and quantum-science through workshops with hands-on activities.Technical abstract:This CAREER project aims to investigate how a mechanical resonator can be used to characterize quantum mechanical properties of qubits realized in a double quantum dot such as tunnel coupling, relaxation and coherence, by adopting a mechanical charge sensing technique based on atomic force microscopy. The use of scannable probes makes it possible to characterize double quantum dots by positioning the probe above the target quantum dot, without integrating a resonator or sensing electrodes nearby. The outcome of this project will broaden the fundamental understanding of the coupling between mechanical resonators and qubits based on double quantum dots and will open the path for the study of a broad range of nanomaterials – nanoparticle complexes, nanowires, self­-assembled quantum dots and engineered molecules– that have not been investigated as qubits. These qubits could operate at much higher temperatures due to their higher confinement energy, enabling wider spread use of quantum technology. The project will support the training of graduate and undergraduate students in advanced cryogenic scanning probe microscopy instrumentation and nanofabrication.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.