A relatively simple plug-and-play control system of quantum key distribution （QKD） based on PCI7300 card is demonstrated, including mechanism design, key generation and key acquisition. The system works very well at the repetition frequency of 1 MHz, and the key generation rate is 100 k/s. A visibility of better than 95% over 50 km-long fiber at 1.31 gm is obtained, which is stable under ordinary lab conditions for 24 h without any feedback control or adjustment. The presented system is a quite promising candidate to realize the QKD in the future.
We present an entanglement analysis protocol on entangled electron spins using quantum dot(QD)and microcavity coupled system.Each quantum dot is placed in the microcavity and ancilla photon input-output process could be used to check the parity of the quantum dots.After the parity check process,the user only needs to measure the spin direction of the QD spin,and the state information can be readout completely.The feasibility of our scheme and the experimental challenge are discussed by considering currently available techniques.
This paper proposes a well-performing hybrid-type truly quantum random number generator based on the time interval between two independent single-photon detection signals, which is practical and intuitive, and generates the initial random number sources from a combination of multiple existing random number sources. A time-to-amplitude converter and multichannel analyzer are used for qualitative analysis to demonstrate that each and every step is random. Furthermore, a carefully designed data acquisition system is used to obtain a high-quality random sequence. Our scheme is simple and proves that the random number bit rate can be dramatically increased to satisfy practical requirements.
