Quantum gate broadcasting on directed acyclic graphs
Phys. Rev. A 114, 012611 – Published 13 July, 2026
DOI: https://doi.org/10.1103/mdxj-znn1
Abstract
Using a generalized quantum gate teleportation protocol, copies of a gate encoding a known or unknown parameter can be sent to multiple receivers. We extend this quantum gate broadcast protocol to a quantum network on directed acyclic graphs in which agents can add phase gates to be distributed and pass unknown phase gates to subsequent receivers. The broadcast resource state is defined by a sequential local unitary circuit over the graph and requires a unitary circuit depth equal to the distance from the sink to the source of the directed acyclic graph, similarly to the Greenberger-Horne-Zeilinger state on a spin chain. We show that, using projective measurements and feedforward unitary operations, the broadcast resource state can be prepared efficiently in finite time.
