This project is conceived in the context of the NSF's call for Research Advanced by Interdisciplinary Science and Engineering (RAISE), and specifically a Dear Colleague Letter for Engineering Quantum Integrated Platforms for Quantum Communication (EQuIP). It addresses a grand challenge of 21st-century science: leveraging modern capabilities in materials science, nanofabrication, signal processing, and integrated systems-on-a-chip to harness the computational power and sensitivity of quantum-coherent systems for practical applications. Motivated by the clear potential of spin-based quantum devices, this RAISE-EQuIP project adopts an engineering approach to address a series of technological roadblocks that currently limit their performance and scalability. The interdisciplinary approach harnesses state-of-the-art classical and quantum signal processing, electronic circuit design in silicon-based integrated platforms, machine learning optimization, and nanophotonic design, with the aim to transform spin-based quantum registers from a laboratory-scale experiments into compact, integrated systems that are available to power new applications and scientific investigations. With superior performance offered under real-world constraints, these devices can be deployed in testbed quantum communication networks and will enable future investigations of fundamental quantum physics. The collaborative project will engage many undergraduate and graduate students from diverse backgrounds; its research goals are coupled with a broad educational mission to educate students and the public about the emerging field of quantum science and technology. Through the realization of compact, robust, low-cost quantum devices, this project will support the design and deployment of hands-on activities for K-12 students and the public about spins, photons, and quantum communication, for use at venues that target large, diverse populations in Philadelphia, PA and Providence, RI.
Clusters of nuclear spins coupled to an optically addressable electron-spin qubit such as the nitrogen-vacancy (NV) center in diamond are leading platforms for quantum communication. The cluster constitutes a register of qubits that can be individually addressed, entangled, stored for times exceeding 1s, and utilized for quantum error correction. However, state-of-the-art experiments are currently performed on laboratory-scale setups consisting of customized optical cryostats, vibration-sensitive free-space optics, and racks of microwave electronics. Performance is further impeded by sub-optimal photon collection efficiency and labor-intensive calibration requirements for quantum control sequences. This RAISE-EQuIP project will tackle these challenges on multiple levels, drawing on complementary expertise of the collaborating researchers in diamond NV quantum control and device engineering (Bassett), high-speed analog circuit design and signal processing (Aflatouni), and computational physics and nanophotonics (Zia). We will design and build compact, fiber-coupled diamond devices featuring nanofabricated optical metalenses and impedance-matched microwave antennas to transmit optical and spin-resonance signals, respectively, and integrate these devices with custom-fabricated silicon CMOS chips that process the necessary analog and digital signals for spin resonance, photon counting, and real-time adaptive feedback control. Computational machine learning methods will enable efficient mapping and control of the unknown coupled-spin Hamiltonian. The resulting quantum-register devices will exhibit performance superior to state-of-the-art laboratory systems, but with a fraction of the size, cost, and energy requirements. Components of the modular, hybrid-integrated system are generalizable to other quantum architectures based on spins, ions, photons, and superconducting qubits, so these devices can serve as a framework for future generations of portable quantum technologies.
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.
