Communication Cost in Simulating Unknown Entangled States

We demonstrate how to universally simulate ensemble statistics of projective local measurements on any n-qubit state shared among n observers with classical communication and shared randomness. Our technique originates from protocols designed to simulate quantum non-locality [in Horizons of the Mind, Springer, Cham (2014)] and classical simulation of quantum circuits [Phys. Rev. Lett. 115, 070501 (2015)]. The protocol preserves three crucial aspects of the simulated quantum scenario in contrast to other approaches: no involvement of additional parties, none of the observers knows the global state of the system, and local measurement settings remain undisclosed.