Quantum Photonics in Space and Time

The realization of complex quantum networks that efficiently distribute entanglement over large-scale distances remains a central challenge in quantum technologies, while offering the potential for breakthrough next-generation applications. Entanglement-based quantum communication can provide the ultimate form of security that is independent of any devices used, distributed quantum computing protocols promise a scalable approach to fault-tolerant quantum computing that will revolutionize information processing, and distributed quantum sensing schemes enable sensor networks to reach the ultimate limits of sensitivity. While entanglement lies at the heart of these exciting technologies, its efficient generation, noise-robust distribution, and practical measurement are key challenges that must be overcome for the realization of a real-world quantum network infrastructure. QUEST will harness the multi-modal properties of light in space and time to target specific technology bottlenecks that limit the scalability of quantum networks today. QUEST will develop a versatile device that performs programmable transformations of spatially structured quantum light and use it to address key challenges in entanglement generation, distribution, and measurement. QUEST will engineer deterministic sources of multipartite and high-dimensional entanglement and develop methods for the generalized measurement and manipulation of high-dimensional entanglement encoded in the photonic spatiotemporal degrees-of-freedom. QUEST will in turn apply these technologies in quantum protocols that achieve noise and loss-robust distribution of the strongest forms of entanglement over deployed fiber networks spanning multiple distance scales. In doing so, QUEST will open a pathway towards scalable and reliable entanglement networks that enable next-generation technologies for communication, computation, and sensing.