Quantum superposition of the order of parties as a communication resource

Author(s): A. Feix, M. Araújo, Č. Brukner

Journal: Phys. Rev. A

Volume: 92

Page(s): 052326

Year: 2015

DOI Number: http://dx.doi.org/10.1103/PhysRevA.92.052326

Link: Link to publication


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. In a more general context, our result also provides semi-device-independent certification of the absence of a definite order of communication.

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