Controlled Remote State Preparation Via Non-ideal Entangled Channel

Quantum communication is the core content of quantum information, which provides a new way for securely transmitting message. Remote state preparation (RSP) can realize the secure transmission of a known state by utilizing shared entanglement and classical communication. As one of the important quantum communication methods, RSP has made a great deal of achievements both in theory and experiment, and has broad prospects for the development and application.In this paper, we mainly develop schemes to realize controlled remote state prepa-ration (CRSP) via the non-ideal channels. The content relates to the controlled remote preparation of arbitrary four-qubit cluster-type state and ?-type state, two-way controlled remote preparation of arbitrary single-qubit states under noisy environment. The princi-pal results in the paper are briefly summarized as follows:1?By constructing sets of ingenious measurement bases at the sender's and the con-troller's locations, two schemes are proposed to realize the controlled remote preparation of an arbitrary four-qubit cluster-type state via partially entangled channels. The re-ceiver can reestablish the prepared state with the success probabilities 50% and 100%,respectively. Compared with the previous proposals, neither auxiliary qubits nor two-qubit unitary transformations are required in the schemes. And the success probabilities are independent of the coefficients of the entangled channel. Moreover, we present two schemes to realize controlled remote preparation of an arbitrary four-qubit ?-state via partially entangled quantum resource. The success probabilities of the two schemes can reach 50% and 100%, respectively.2?By constructing a ingenious seven-qubit maximally entangled state as the quantum channel, a scheme is proposed to implement bidirectional controlled remote preparation.The two communication parties can simultaneously exchange an arbitrary single-qubit state with unit success probability. Then we consider the influence of two important decoherence noises (the amplitude-damping noise and phase-damping noise) on the bidi-rectional CRSP protocol. The fidelity is used to describe how close the output state and the prepared state are. The relation between the decoherence noisy rate and the the fidelity is analyzed.