Wang Xiang-bin

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A conditional geometric phase shift gate, which is fault tolerant to certain types of errors due to its geometric nature, was realized recently via nuclear magnetic resonance (NMR) under adiabatic conditions. However, in quantum computation, everything must be completed within the decoherence time. The adiabatic condition makes any fast conditional Berry(More)
To transmit an unknown qubit robustly through the noisy channel, one may first encode it into a certain quantum error correction code and then transmit it. The remote party decodes it and stores it. Sending a qubit in such a way can significantly reduces the error rate compared with directly sending the qubit itself. Here we show how to realize such a(More)
It is conjectured that the an entanglement output states from a beam splitter requires the non-classicality in the input state(M. Here we give a proof for this conjecture. The beam splitter is one of the few quantum devices that may act as the entangler. The entangler properties of a beam splitter have been studied in the past [1–4]. In particular, Kim et(More)
We propose a scheme to produce the maximally two photon polarization entangled state(EPR state) with single photon sources and the passive linear optics devices. In particular, our scheme only requires the normal photon detectors which distinguish the vacuum and non-vacuum Fock number states. A sophisticated photon detector distinguishing one-photon state(More)
Motivated for the fault tolerant quantum computation, a quantum gate by adi-abatic geometric phase shift is extensively investigated recently. Due to the enviromental noise, the decoherence time for a quantum state can be very short. In the adiabatic quantum computation, if we change the Hamiltonian slowly, the decoherence error is increased, if we change(More)
We show that, if any classical errorcation(CE) and privicy amplification(PA) scheme used to distill the final key in the quantum key distribution is unsecure, it will cause contradicts in the pure classical case. Thus we draw the conclusion that all secure CE and PA are secure for the final key distillation in the quantum key distribution Since Bennett and(More)
We consider a strategic problem of the Evesdropping to quantum key distribution. Evesdropper hopes to obtain the maxium information given the disturbance to the qubits is often For this strategy, the optimized individual attack have been extensively constructed under various conditions. However, it seems a difficult task in the case of coherent attack,(More)