Efficient multiparty-to-multiparty quantum secret sharing via continuous variable operations

The one-to-multiparty quantum secret sharing scheme [Phys. Rev. A 71 (2005) 044301] proposed recently is extended to a multiparty-to-multiparty case. Furthermore, the continuous variable operations are employed in the extended scheme to replace the specific discrete unitary operations used in the original scheme. The complete randomicity of the continuous variable characterizing the unitary operations can ensure the security of secret sharing. Moreover, the present scheme is compared with the recent similar scheme [Phys. Rev. A 72 (2005) 012304]. It is found that the efficiency of the present scheme is n times of that of the previous one.