Asymmetric multi-party quantum state sharing of an arbitrary m-qubit state

Abstract

We present a scheme for asymmetric multi-party quantum state sharing of an arbitrary m-qubit state with n agents. The sender Alice first shares m ? 1 Bell states and one n + 1-particle Greenberger---Horne---Zeilinger state with n agents, where the agent Bob, who is designated to recover the original m-qubit state, just keeps m particles and other agents (all controllers) n ? 1 particles, that is, each controller only holds one particle in hand. Subsequently, Alice performs m Bell-basis measurements on her 2m particles and each controller only need take a single-particle measurement on his particle with the basis X. Finally, Bob can recover the original m-qubit state with the corresponding local unitary operations according to Alice and all controllers' measurement results. Its intrinsic efficiency for qubits approaches 100%, and the total efficiency really approaches the maximal value, which is higher than those of the known symmetric schemes.