Quantum Network Communication

Riccardo Bassoli, Holger Boche, Christian Deppe +4 more

Ze-Zhou Sun, Yuan-Bin Cheng, Dong Ruan +3 more

Quantum network extends the ability to transmit information securely from two-party communication to multi-party communication with arbitrarily long distances. The efficiency of secure communication in a quantum network depends on both the topology of the network and the strategy of communication relays. In this paper, we propose a strategy to build a quantum network integrating various types of quantum secure direct communication (QSDC) schemes. A cost optimization model is presented to measure the cost of transmitting secure messages in a quantum network. Within the model, two types of quantum network strategies, the quantum circuit switching strategy and the quantum packet switching strategy, are proposed and compared. Numerical simulations in a specific network show that the quantum packet switching strategy is more favorable in future quantum networks taking into account robustness and cost required when using different types of QSDC schemes.

Alexander V. Sergienko, Villoresi, Paolo, Saverio Pascazio

Harumichi Nishimura

Considering extensive studies on network coding and quantum information theory in this century, it was just a matter of time that the study of quantum network coding was initiated. In some sense, it is rather important to ask if the amount of quantum bits communicated on a network can be reduced by allowing encoding at intermediate nodes on the network since quantum communication is much more expensive than classical communication in principle. The first result by Hayashi et al. in 2006 was basically negative for this question - quantum network coding does not give any benefit for reducing the amount of qubits sent on the butterfly network. However, this was just the first step to explore the theory of quantum network coding. After their work, it has been shown that the amount of communicated qubits can be reduced in several changes of the settings such as by allowing extra classical communication, while there has been further negative results. In this paper, we review the basic concept of quantum network coding, and report the currently known positive and negative results on quantum network coding in various settings.

Xi Chen, Heming Wang, Dan-Tong Ji +2 more

Quantum communication between nodes in quantum networks plays an important role in quantum information processing. Here, we proposed the use of the expected number of quantum channels as a measure of the efficiency of quantum communication for quantum networks. This measure quantified the amount of quantum information that can be teleported between nodes in a quantum network, which differs from classical case in that the quantum channels will be consumed if teleportation is performed. We further demonstrated that the expected number of quantum channels represents local correlations depicted by effective circles. Significantly, capacity of quantum communication of quantum networks quantified by ENQC is independent of distance for the communicating nodes, if the effective circles of communication nodes are not overlapped. The expected number of quantum channels can be enhanced through transformations of the lattice configurations of quantum networks via entanglement swapping. Our results can shed lights on the study of quantum communication in quantum networks.

Michel Le Bellac