Multiparty quantum-state sharing of an arbitrary two-particle state with Einstein-Podolsky-Rosen pairs

A scheme for multiparty quantum state sharing of an arbitrary two-particle state is presented with Einstein-Podolsky-Rosen pairs. Any one of the $N$ agents has the access to regenerate the original state with two local unitary operations if he collaborates with the other agents, say the controllers. Moreover, each of the controllers is required to take only a product measurement ${\sigma }_x\otimes {\sigma }_x$ on his two particles, which makes this scheme more convenient for the agents in the applications on a network than others. As all the quantum source can be used to carry the useful information, the intrinsic efficiency of qubits approaches the maximal value. With a new notation for the multipartite entanglement, the sender need only publish two bits of classical information for each measurement, which reduces the information exchanged largely.

Figure 1

(Color online) Multiparty quantum secret sharing for an arbitrary two-particle state with two agents. The single lines denote qubits, double lines denote classical data, similar to Ref. 21. $M_1$, $M_2$ are the GHZ-state joint measurements on the particles $x{a}_1{a}_2$ and $y{c}_1{c}_2$, respectively; $M_B$ is the product measurement ${\sigma }_x\otimes {\sigma }_x$ on the particles $b_1{d}_1$.