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By constructing sets of ingenious measurement bases at the sender's and the controller's locations, we devise two schemes to realize the controlled remote preparation of an arbitrary four-qubit χ-state via partially entangled quantum resource. The success probabilities of the proposed schemes are 50 % and 100 %, respectively. It means that the success probabilities are independent of the coefficients of the entangled channel. [ABSTRACT FROM AUTHOR]

Two controlled remote state preparation protocols via the Brown state as the entangled channel are proposed. One prepares an arbitrary two-qubit state, and the other prepares an arbitrary three-qubit state. It is worth mentioning that Hurwitz matrix equation plays a key role in the construction of measurement basis. Comparing with the previous protocols, the novel schemes have no restriction on the coefficients of the prepared state while keeping the same success probability 50 %. It means that the application of the proposed schemes are more extensive in practice. Moreover, we discuss the special complex coefficient ensembles with unit success probability. [ABSTRACT FROM AUTHOR]

Two schemes via different entangled resources as the quantum channel are proposed to realize remote preparation of an arbitrary four-particle $$\chi $$ -state with high success probabilities. To design these protocols, some useful and general measurement bases are constructed, which have no restrictions on the coefficients of the prepared states. It is shown that through a four-particle projective measurement and two-step three-particle projective measurement under the novel sets of mutually orthogonal basis vectors, the original state can be prepared with the probability 50 and 100 %, respectively. And for the first scheme, the special cases of the prepared state that the success probability reaches up to 100 % are discussed by the permutation group. Furthermore, the present schemes are extended to the non-maximally entangled quantum channel, and the classical communication costs are calculated. [ABSTRACT FROM AUTHOR]

Two novel schemes via different entanglement resources are put forward to remotely preparing a five-qubit Brown-type state with high probabilities. To design the schemes, some useful measurement bases with the aid of Hurwitz matrix equation are constructed, which have no restrictions on the coefficients of the prepared state. Through a four-particle projective measurement and two-step three-particle projective measurement under the novel sets of mutually orthogonal basis vectors, the remote preparation can be realized with the probability 50% and 100% in general case, respectively. To improve the probability, the special ensembles of the prepared state that the success probability reaches up to 100% are discussed for the first scheme by the permutation group. Furthermore, the present schemes are extended to the nonmaximally entangled quantum channel. [ABSTRACT FROM AUTHOR]

By constructing some useful measurement bases, we put forward two novel schemes via different entanglement resources to realize remote preparation of a six-particle entangled cluster-type state with high probabilities. It is shown that through a three-particle projective measurement and two-step two-particle projective measurement under the novel sets of mutually orthogonal basis vectors, the original state can be prepared with the probability 50 % and 100 %, respectively. And for the first scheme, the special cases of the prepared state that the success probability reaches up to 100 % are discussed by the permutation group. Compared with the previous proposal, the success probabilities of the proposed schemes are greatly improved. Furthermore, the present schemes are extended to the non-maximally entangled quantum channel, and the classical communication costs are calculated. [ABSTRACT FROM AUTHOR]

Abstract: Our concern is to remotely prepare a four-particle entangled cluster-type state with high success probabilities. By constructing some useful measurement bases, two novel schemes via different entanglement resources as the quantum channel are designed: one is via an EPR pair and two three-particle GHZ states; the other is via two four-qubit GHZ states. It is shown that through four-particle projective measurements under the novel sets of mutually orthogonal basis vectors, the original state can be successfully prepared with the probabilities and 1, respectively. These schemes are extended to the non-maximally entangled quantum channel. Compared with the previous remote preparation proposal, the success probabilities of the proposed schemes are greatly improved. Furthermore, the classical communication costs of these schemes are calculated to determine the classical resources required. [Copyright &y& Elsevier]

We propose a deterministic and faithful scheme for realizing the assisted clone of an unknown two-particle entangled state. The first stage of the protocol requires teleportation via maximal entanglement. In the second stage, a novel set of mutually orthogonal basis vectors is constructed. With the assistance of the preparer through a two-particle projective measurement under this basis, a perfect copy of an original state can be produced. Compared with the previous protocols which produce the unknown state and its orthogonal complement state at the site of the sender, our scheme generates the unknown state deterministically. On the other hand, we put forward another assisted clone scheme via nonmaximal entanglement as the quantum channel. A faithful copy of the unknown state can be obtained with a certain probability. [ABSTRACT FROM AUTHOR]

Abstract: Following some ideas of the quantum network coding protocol [Phys. Rev. A 76 (2007) 040301], we propose an efficient protocol to transmit two 2-level quantum states crossly over the butterfly network with two non-maximally entangled qubit pairs shared only between two senders. It is shown that both of the receivers can reestablish the initial states with a certain probability. And one classical bit communication can be saved at the bottleneck channel. Moreover, this protocol is generalized to the case of transmitting two multipartite entangled states. [Copyright &y& Elsevier]

In this paper, we show that some special mixed quantum resource experience the same property of pure entanglement such as Bell state for quantum teleportation. It is shown that one mixed state and three bits of classical communication cost can be used to teleport one unknown qubit compared with two bits via pure resources. The schemes are easily implement with model physical techniques. Moreover, these resources are also optimal and typical for faithfully remotely prepare an arbitrary qubit, two-qubit and three-qubit states with mixed quantum resources. Our schemes are completed as same as those with pure quantum entanglement resources except only 1 bit additional classical communication cost required. The success probability is independent of the form of the mixed resources. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, by constructing some useful measurement bases, we first show that two senders can jointly prepare a three-qubit state of complex coefficients to a remote receiver via the shared three GHZ states. Then, the success probability can be improved by using the permutation group to classify the preparation state. Furthermore, under some different measurement bases, we propose another scheme to jointly prepare a three-qubit state of real coefficients with less restrictions. Finally, the present schemes are extended to multi-sender, and the classical communication costs of all the schemes are also calculated. [ABSTRACT FROM AUTHOR]