NQVL: QSTD: Pilot: SCY-QNet: Wide-Area Quantum Network To Demonstrate Quantum Advantage

Large and robust quantum computers have the power to considerably alter many aspects of society and economy, ranging from science, medicine, and engineering to manufacturing, logistics, and finance. Such quantum systems appear plausible only as a network of smaller quantum computers. Quantum Networks also enable secure and privacy-preserving long-distance communication, unlike classical systems. This project aims to build a 10-node quantum network called SCY-QNet, connecting quantum computers at Stony Brook, Columbia, Yale, and Brookhaven National Laboratory. SCY-QNet is intended as a user-configurable shared infrastructure for scientists and engineers to develop and validate research and experiments in quantum communication and computing. The key scientific challenges in building SCY-QNet include developing robust quantum processing units and quantum memories, and quantum communication infrastructure, including free-space optical quantum links. The project aims to demonstrate the unique capabilities of quantum systems in secret key sharing, and quantum communication, simulation, and computation. The goal of the workforce development activities in the project is to create a diverse quantum-smart workforce capable of propelling quantum-driven economic development. Success in this project will pave the way for the construction of quantum computing platforms that can enable applications infeasible with classical systems. The key scientific challenges in building SCY-QNet include developing robust heralded quantum memories, efficient quantum repeater systems, and QPUs with efficient in-out qubit-photon coupling. The project has six research components: (i) Developing banks of heralded quantum memories with sufficient storage times and retrieval efficiency. (ii) Developing robust quantum repeater systems, including high-rate entanglement sources and efficient swapping devices. (iii) Developing quantum processing units (QPUs) with atom-based qubits that facilitate high entanglement rates with atom-based memories. The project aims to develop these by integrating compact optical cavities that enable efficient coupling of photons. (iv) Developing high-efficiency quantum frequency conversion units to bridge the frequency difference between quantum memory banks and QPUs, as well as converting the infrared photons from memories to telecom photons to transmit entangled photons. (v) Developing quantum network communication infrastructure, including the development of free-space optical links for transmitting qubits over long-distance, and developing a network stack with software-defined control modules that orchestrate the generation and distribution of entanglements. (vi) Demonstration of quantum advantage via a series of experiments, including secret-key sharing protocols, remote entanglement distribution, distributed simulation of quantum physical systems, and distributed computation of quantum algorithms that are known to have quantum advantage. This project advances the objectives of Quantum Information Science and Engineering at NSF in response to the National Quantum Initiative Act for the continued leadership of the United States in QIS and its technology applications. 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.