Abstract:
A quantum network, i.e., a set of nodes connected by sources of bipartite and local multipartite Greenberger-Horne-Zeilinger (GHZ) quantum states, is considered, corresponding to the structure of a graph or hypergraph. The problem of distilling a conference secret key and a global GHZ state with the maximum possible speed is considered under the following class of bounded operations: local operations and shared randomness followed by arbitrary classical postprocessing. This is a quantum analogue of a well-known problem in classical multiterminal information theory [1]. Upper bounds on the throughput are derived, cases where it is possible to obtain an exact value of the throughput are discussed, and difficulties in generalizing these results are discussed. The talk will be based on the paper [2] and some later unpublished results.
[1] I. Csiszar and P. Narayan, Secrecy capacities for multiple terminals, IEEE Trans. Inf. Theory, 2004, http://dx.doi.org/10.1109/TIT.2004.838380
[2] A. Trushechkin, H. Kampermann, and D. Bruss, Spanning tree packing protocol for conference key propagation in quantum networks, https://arxiv.org/abs/2506.04105
