NSF Award
2328822
Non-technical Abstract: Quantum technologies are expected to become integral to the future sustained economic well-being of the country. Quantum computing and quantum sensing are essential parts of evolving quantum technologies. While many quantum technologies, such as quantum computers based on superconducting qubits, are already available to do advanced calculations, the need for ultra-low (< 0.1K) temperatures makes them challenging and less accessible. The team focuses on studying and controlling the quantum decoherence in hybrid diamond spin qubit-magnetic excitation (magnon) systems that could potentially serve as scalable quantum information processing platforms operating at higher temperatures (≥ 1 K) than superconducting qubits. The project's goals are to design, fabricate, characterize, and model hybrid architectures where diamond spin qubits and their interactions are controlled by magnons and spin current effects using heterostructures of thin-film or two-dimensional magnetic materials. The principal investigators at Wichita State University benefit from extending the capabilities in advanced nanofabrication of quantum materials and cryogenic quantum sensing from the University of Nebraska-Lincoln. The project also aims to advance education and build a workforce in emerging quantum technologies by training a postdoc, several graduate/undergraduate/K-12 (abbreviating Kindergarten through 12th grade) students, and four K-12 teachers.<br/><br/>Technical Abstract: The realization of chip-integrated, spin-based quantum information processing (QIP) devices depends on the ability to controllably link distant spin qubits via a coherent quantum bus. To achieve direct spin-spin qubits coupling, architectures based on linear chains of spin defects positioned on the surface of wide-bandgap semiconductors have been proposed, but the short range (~ 10 nm) of the dipolar interaction between neighbors and disorder in their relative positions impose engineering challenges that are currently difficult to overcome. The goals of the project are to design, fabricate, characterize, and model hybrid architectures where diamond nitrogen-vacancy (NV) spin qubits (SQs) and their interactions are controlled by magnonics and spintronics effects using heterostructures of thin-film and two-dimensional (2D) magnetic materials. The project seeks to study SQ-magnon couplings in magnetic nanowires, 2D flakes, and cavities with different shapes and compositions and at a wide range of temperatures (0.3-350 K) and magnetic fields (up to 3 T) with the goal to identify the physical mechanisms of the rich magnetic excitation modes in magnetic materials at the nanoscale, the origin of decoherence in hybrid diamond SQ-magnon systems, and the optimal working parameters for using (classical and quantum) magnons to couple distant SQs without affecting their coherence. The proposed research activities include: (i) growth of magnetic materials (thin film, 2D) and nanofabrication of spintronic devices for generating and controlling magnons, (ii) perform static and dynamic magnetic, optical, and magneto-transport measurements, (iii) perform quantum sensing of magnons in thin-film and 2D magnets at ambient and cryogenic conditions to study the rich physics of spin excitations and explore quantum magnons, (iv) and finally establish theoretically and experimentally the strong coherent coupling between NV SQs and magnons relevant to QIP. The principal investigator at University of Nebraska Lincoln (UNL) helps the principal investigators at Wichita State University to extend UNL's quantum capabilities in advanced nanofabrication of quantum materials (diamond membranes doped with NVs, magnetic waveguides/devices) and cryogenic quantum sensing. The workforce development goal of this project is to train and mentor students in quantum information science (QIS) and technologies. As a new field with distinct knowledge and skills required to be competitive in the emerging quantum workforce, an opportunity exists to design innovative curricula for training graduate and undergraduate students and to create new education and outreach activities that integrate quantum concepts to recruit first-generation quantum scientists and engineers. The workforce development plans include: (1) design an applied learning module for quantum technologies course, (2) design traditional and animation-based course modules for emerging QIS technologies, (3) education, training, and mentoring Plans for K-12 Teachers and K-12 Students, and (4) promote inclusive and equitable research plan.<br/><br/>This project is jointly funded by The Office of Multidisciplinary Activities (MPS/OMA), the Established Program to Stimulate Competitive Research (EPSCoR), and Technology Frontiers Program (TIP/TF).<br/><br/>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.
