非平衡基的连续变量量子密码方案

摘要 在非平衡基下，通过局域操作引入纠缠态的非对称性，证明了非平衡基可以提高连续变量量子密码方案的密钥生成速率.以典型的密钥分配实验为例，经过数值计算验证，在同等密钥生成速率的条件下，非平衡基的量子密钥分配安全距离可以扩展20 km左右.
With its security based on quantum no-cloning and Heisenberg uncertainty relation, the quantum cryptography is a newly developed key distribution protocol. The recent research on continuous variable quantum cryptography assumes that the choice of basis is balanced. However, the performance of continuous variable quantum cryptography is an interesting but open question. By introducing the asymmetry in the shared bipartite two-mode entanglement state, the secret key rate was improved with unbalanced basis. Furthermore, numerical simulations with typical continuous variable quantum key distribution experiment show that the secure distance can be prolonged by 20km for a given secure key rate.