Abstract
Multipartite entangled states are a fundamental resource for a wide range of quantum information processing tasks. In particular, in quantum networks, it is essential for the parties involved to be able to verify if entanglement is present before they carry out a given distributed task. Here we design and experimentally demonstrate a protocol that allows any party in a network to check if a source is distributing a genuinely multipartite entangled state, even in the presence of untrusted parties. The protocol remains secure against dishonest behaviour of the source and other parties, including the use of system imperfections to their advantage. We demonstrate the verification protocol in a three- and four-party setting using polarization-entangled photons, highlighting its potential for realistic photonic quantum communication and networking applications.
Highlights
To cite this version: Will Mc Cutcheon, Anna Pappa, Bryn Bell, Alex Mcmillan, André Chailloux, et al
The advantage provided by entangled states can be observed, for example, when the quantum correlations of the n-party Greenberger–Horne– Zeilinger (GHZ) state[6] are used to win a nonlocal game with probability 1, while any classical local theory can win the game with probability at most 3/4
The results we have presented are situated in a realistic context of distributed communication over photonic quantum networks: we have shown that it is possible for a party in such a network to verify the presence of genuine multipartite entanglement (GME) in a shared resource, even when some of the parties are not trusted, including the source of the resource itself
Summary
To cite this version: Will Mc Cutcheon, Anna Pappa, Bryn Bell, Alex Mcmillan, André Chailloux, et al. In a more general setting, multipartite entangled states allow the parties in a network to perform distributed tasks that outperform their classical counterparts[8], to delegate quantum computation to untrusted servers[9], or to compute through the measurementbased quantum computation model[10]. It is vital for parties in a quantum network to be able to verify that a state is entangled, especially in the presence of untrusted parties and by performing only local operations and classical communication
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