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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]

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]