Quantum technologies explore the possibility of harnessing the power of quantum properties of physical systems to demonstrate in practice an advantage in terms of computational time, security or communication efficiency. Such an advantage can revolutionize current practices in information processing and communication, with a range of applications in financial, government and medical transactions, critical infrastructure protection, material design, network management, and many more. The deployment however of a large-scale quantum network connecting devices such as quantum computers or sensors that would be able to unlock the full potential of quantum resources may lie several years ahead. While we advance in this direction, it is crucial to demonstrate that current and near-term quantum technologies can already be exploited for enabling or enhancing useful tasks in a way that cannot be achieved by classical means.
In QUSCO, we pursued this objective using photonic systems, where information is typically encoded in properties of single or entangled photons. The photonic experimental platform is perfectly suited for communication of quantum information thanks to the inherent robustness of photons to losses during propagation. It can also be used currently for performing small-scale quantum computations and additionally provides a promising path to integration, which can drastically enhance the scalability of the resulting systems. Based on this technology and on a strong interaction between experimental physics and theoretical computer science, we conceived and implemented throughout the project advanced communication and computation tasks exhibiting a provable quantum advantage. Our demonstrations allow us to conclude that photonic quantum technologies can be used today for showing quantum advantage with practical resources for compelling applications, hence successfully achieving the primary objective of this action.
