Abstract
The Bell inequality can provide a useful witness for device-independent applications with quantum (or postquantum) eavesdroppers. This feature holds only for single entangled systems. Our goal is to explore a device-independent model for quantum networks. We first propose a Bell inequality to verify the genuinely multipartite nonlocality of connected quantum networks including cyclic networks and universal quantum computational resources for a measurement-based computation model. This is further used to construct a monogamy relation in a fully device-independent model with multisource quantum resources. It is finally applied for multiparty quantum key distribution, blind quantum computation, and quantum secret sharing. The present model can inspire various large-scale applications on quantum networks in a device-independent manner.
Highlights
The Bell theorem states that the statistics generated by local measurements on a two-spin entanglement cannot be generated by any classical local model under the locality and causality assumptions
Compared with single entangled systems, there is great difficulty in characterizing multipartite correlations of quantum networks because of the independent assumption of sources and local joint measurement allowed for each party
In most secure tasks, such as quantum key distribution (QKD) [5], the trustworthiness of quantum devices according to certain specifications should be avoided in order to enable adversary-tolerant realizations [6]
Summary
The Bell theorem states that the statistics generated by local measurements on a two-spin entanglement cannot be generated by any classical local model under the locality and causality assumptions. In most secure tasks, such as quantum key distribution (QKD) [5], the trustworthiness of quantum devices according to certain specifications should be avoided in order to enable adversary (noise)-tolerant realizations [6] These socalled device-independent scenarios only make use of the statistics of measurement outcomes [28–30]. Our goal in this work is to propose a device-independent model for secure information processing in general quantum networks against quantum (or postquantum) eavesdroppers. Compared with a recent result for ring-shaped networks [34], the proposed inequality provides the first Bell test for verifying general cyclic networks This further implies a new feature for characterizing the leaked information in device-independent tasks on quantum networks going beyond single entangled systems [6–8,28– 30] or device-independent models [31,32]. These results can inspire interesting applications on large-scale quantum networks in a device-independent manner
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