Quantum superposition of the order of parties as a communication resource

Understand

In a variant of communication complexity tasks, two or more separated parties cooperate to compute a function of their local data, using a limited amount of communication.

• It is known that communication of quantum systems and shared entanglement can increase the probability for the parties to arrive at the correct value of the function, compared to classical resources.
• Here we show that quantum superpositions of the direction of communication between parties can also serve as a resource to improve the probability of success.
• We present a tripartite task for which such a superposition provides an advantage compared to the case where the parties communicate in a fixed order.