Grant: Research Tools and Instruments

Among the zoo of candidate quantum computing platforms, neutral-atom tweezer arrays offer the prospect of scalable, adaptable, and efficient quantum computing. To enable the gate operations that facilitated quantum computations, atomic Rydberg transitions must be addressed with precision laser systems. As quantum processing units (QPUs), neutral-atom tweezer arrays may also hold another advantage: their inherent optical transitions are compatible with short- and long-distance quantum communications systems (with room-temperature fiber optic links), opening up the possibility for distributed quantum computing. Just as in classical computing, there will always be demand for more processing power than a single QPU can offer, which requires linking them together; however, unlike classical computing, these links require distributed quantum entanglement, a demanding resource. Here, we propose equipping the lab's rubidium-atom tweezer-array quantum processing unit (QPU) with Rydberg entanglement functionality, both bringing it the capacity to perform universal quantum computations, and exploring a unique quantum-memory-inspired scheme for distributed entanglement and quantum computing. We request two lasers at 480 nm and 780 nm, and an ultrastable reference cavity made of ultralow expansion (ULE) glass housed in ultrahigh vacuum with precision temperature control, to lock the laser frequencies to below 100 Hz phase noise and linewidth. With these Rydberg lasers, entanglement can be established between individual tweezer-trapped atoms and a small quantum memory spin-wave ensemble, from which a novel, efficient, entanglement-preserving interconnect between the QPU and optical links can be established. The requested Rydberg lasers will enable valuable new research, and will be a key platform for advancing quantum computing functionality in the University of Alberta's atomic physics lab, one of Canada's leading quantum technologies research spaces. These tools are urgently needed to develop an innovative quantum computing technology and advance Canada's capabilities in this rapidly advancing field of quantum technologies. By adding functionality in distributed quantum computing for use by Canadians, this new tool provides unprecedented training opportunities both in the realm of experiment (hands-on skills working with state-of-the-art equipment and groundbreaking techniques) and theory (to explore new ideas for distributed quantum computing and other applications of long-distance quantum entanglement) in a supportive and diverse team environment. This apparatus with the proposed tools enabling quantum computing operations will become a key tool for national and international colleagues in several established collaborations, and will form the nexus of new projects, all with the benefit of enhancing Canada's leadership in quantum hardware development and training.