For two parties sharing the original state, a scheme for remote preparation of the two-particle entangled state by three partial two-particle entangled states as the quantum channel is presented, and then directly generalize the scheme for remotely preparing a multipartite GHZ-class state for M senders. It is shown that the receiver can obtain the unknown state with certain probability under the condition that only and only if all the senders collaborate with each other. The N -particle projective measurement and the von Neumann measurement are needed in our scheme. The probability of the successful remote state preparation and classical communication cost are calculated.

For M-sender independently share the classical knowledge of a quantum state, a scheme for joint remote preparation of an arbitrary two-qubit state by GHZtype states as the quantum channel is presented. It is shown that the receiver can reconstruct the original state with certain probability under the condition that only and only if all the senders collaborate with each other. The singlequbit and two-qubit projective measurements are needed in our scheme. We also discuss some information-splitting methods which can make the receiver obtain the unknown state.

We theoretically study the quantum interference induced photon blockade phenomenon in atom cavity QED system, where the destructive interference between two different transition pathways prohibits the two-photon excitation. Here, we first explore the single atom cavity QED system via an atom or cavity drive. We show that the cavity-driven case will lead to the quantum interference induced photon blockade under a specific condition, but the atom driven case can't result in such interference induced photon blockade. Then, we investigate the two atoms case, and find that an additional transition pathway appears in the atom-driven case. We show that this additional transition pathway results in the quantum interference induced photon blockade only if the atomic resonant frequency is different from the cavity mode frequency. Moreover, in this case, the condition for realizing the interference induced photon blockade is independent of the system's intrinsic parameters, which can be used to generate antibunched photon source both in weak and strong coupling regimes.

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