Research On The Decoy State Key Distribution And The Entanglement Upper And Lower Bounds Of Stabilizer Codewords

Quantum information is a comprehensive subject which combines quantum mechanics, information theory, computer science and many other basic subjects. It has a wide scope of knowledge.Quantum cryptography communication is a new communication technology which developed rapidly in the last two decades. It is the combination of cryptography and quantum mechanics, using quantum properties to get or improve confidentiality. Quantum key distribution(QKD) is the core of quantum cryptography. Quantum key distribution based on single photon has been proved unconditional security theoretically, but both sides need to have perfect communication conditions can be truly realized. Not perfect single photon source and the channel attenuation in the practical quantum key distribution system will lead to PNS attack, and decoy state scheme can solve PNS attack well. Noise is harmful to information processing systems, we always try to counteract the effect of noise. In quantum information processing, we do the same as classical information processing system, using error-correcting codes to protect quantum information. Entanglement is an important resource of quantum error-correcting codes. It is hoped that entanglement can be quantitatively described. A variety of entanglement measure methods have been proposed, such as the relative entropy of entanglement, the geometric measure and global robustness of entanglement and so on. To stabilizer codes, such three entanglement measures are equivalent.This paper mainly includes two parts. The first one is research on decoy state, and simulation it with BB84protocol. The other one is stabilizer codes, we propose a algorithm from the generators of code to get the entanglement upper and lower bounds, then give some results.