“Quantum networks are at the core of a flurry of quantum information tasks, such as quantum communication, quantum key distribution, and quantum computation, as well as the pillar of the future quantum internet. The most promising way to implement near-term quantum networks resides in using hybrid quantum technologies and taking advantage of different existing approaches. These can be represented, for instance, by different kinds of quantum state sources, various physical systems, and the employment of mixtures of classical and quantum hardware to achieve given tasks. However, most importantly, a user of future quantum networks should be equipped with protocols for the certification of their quantum devices, as well as with privacy when interacting with untrusted nodes. In this talk, I will report on three results related to these topics. First, I will show a concrete example of a hybrid building block platform for quantum network applications, represented by a quantum dot-based plug-and-play polarization-entangled photon source. Second, I will illustrate a machine learning-based approach for the device-independent certification of arbitrarily large and complex quantum networks. Such an approach can be used not only to optimize arbitrary functions over supersets of quantum correlations but also to lower-bound violations of Bell-like inequalities compatibly with experimentally observed sets of correlations. Finally, quantum networks are also pivotal to private collaborative delegated quantum computing tasks. A well-established example is blind quantum computing, which allows a user with minimal quantum resources to delegate a quantum computation to a remote quantum server while keeping private input, output, and details of the computation. In this context, I will report on an experimental proof-of-concept multi-client blind quantum computing protocol, implemented on an adaptive and modular linear photonic network. Such findings may represent significant building blocks for the realization of secure and efficient quantum networks, as well as contribute to establishing new milestones on the roadmap towards the quantum internet.”
Beatrice Polacchi will be visiting the team QI of the laboratory LIP6 Sorbonne University on 22 September.