Quantum Coordination in Multi-User Networks

Quantum communication and computation offer promising solutions and protocols for information processing, security, and distributed networks. Furthermore, state distribution and coordination are essential pre-processing steps for many such protocols. In our work, we analyze coordination under resource constraints in various network models, and establish a clear connection between quantum coordination and nonlocal games with quantum strategies. We present our results on coordination capacity for two types of networks, with either classical or quantum links. For fully quantum networks, we determine the tradeoffs between quantum communication rates for entanglement coordination. Our results highlight the fundamental differences between the coordination of separable and entangled correlations. Specifically, in the cascade network, where Alice sends qubits to Bob and Bob to Charlie, we show that when quantum entanglement is generated, Alice has to send less quantum bits (qubits) to Bob than what Bob needs to send to Charlie.