欠稠密等离子体中诱发的偶次相对论谐波

在自生磁场或背景磁场的作用下,等离子体被磁化.磁化后的欠稠密等离子在超强激光的辐射下诱发相对论相干谐波辐射.由于磁场的影响,诱发的相对论相干谐波辐射中产生偶次谐波辐射.从理论上研究了这一现象,导出了谐波辐射的一般性方程,并特别研究了二次谐波辐射的有关参数 关键词： 二次谐波辐射 自生磁场 强激光 欠稠密等离子体     

Continuous-variable quantum key distribution based on continuous random basis choice

Gaussian-modulated coherent state quantum key distribution is gradually moving towards practical application. Generally, the involved scheme is based on the binary random basis choice. To improve the performance and security, we present a scheme based on a continuous random basis choice. The results show that our scheme obviously improves the performance, such as the secure communication distance. Our scheme avoids comparing the measurement basis and discarding the key bits, and it can be easily implemented with current technology. Moreover, the imperfection of the basis choice can be well removed by the known phase compensation algorithm.     

A secure identification system using coherent states

A quantum identification system based on the transformation of polarization of a mesoscopic coherent state is proposed. Physically, an initial polarization state which carries the identity information is transformed into an arbitrary elliptical polarization state. To verify the identity of a communicator, a reverse procedure is performed by the receiver. For simply describing the transformation procedure, the analytical methods of Poincar\'{e} sphere and quaternion are adopted. Since quantum noise provides such a measurement uncertainty for the eavesdropping that the identity information cannot be retrieved from the elliptical polarization state, the proposed scheme is secure.     

高阶相对论谐波辐射的理论研究

对短脉冲强激光在非稠密均匀等离子体中传播时产生的相对论相干谐波辐射进行了一般性研究．在准稳态近似（ｑｕａｓｉｓｔａｔｉｃ ａｐｐｒｏｘｉｍａｔｉｏｎ）下得出ｎ阶谐波包络的演化方程，并用此方程研究了ｎ阶谐波的增长与饱和及转化效率等问题     

相对论相干三次谐波的饱和

研究了短脉冲强激光在非稠密均匀等离子体中传播时产生的相对论相干三次谐波和饱和问题，在准静态近似（ｑｕｓｉｓｔａｔｉｃａｐｐｒｏｘｍａｔｉｏｎ）下得出波动方程，用此方程计算了三阶谐波的饱和值及失相长度，并分析了影响失相长度的因素。     

Destructive Interference in a A-Type Coherently Driven Mazer

We derive an expression of the interaction between a quantum cavity field and an ultracold A-type three-level atom in which two upper levels are coupled by a coherent driving field. The effects of the driving-induced atomic coherence on the atomic emission probability are investigated. It is found that, due to the driving-induced atomic coherence, there are two transition channels for the atom interacting with the cavity field. Between the two transition channels, there is a quantum interference, which is a destructive interference. This destructive quantum interference suppresses the emission of the atom. The atomic emission probability decreases with the increasing driving field.     

连续变量量子密钥分发系统中调制器驱动设计

相位调制器与振幅调制器是连续变量量子密钥分发中不可缺少的光调制器件.本文以量子安全通信系统的硬件为平台,设计了LiNbO3相位调制器的驱动电路,性能测试电路,同时给出了振幅调制器的性能监控电路.从理论与实验上对方案的可行性与可靠性进行了验证.     

Multi-object quantum traveling ballot scheme

Based on quantum mechanics, a traveling ballot scheme with anonymity and secrecy is introduced to realize voting. By searching the objects in large amount of data bases, every voter may cast votes to his desired candidates. Therefore, the proposed scheme may be applied to voting with a great deal of candidates, such as network voting and so on. The security analysis of the present scheme is also performed.     

基于双模压缩态的量子投票协议

提出了一种基于双模压缩态的基本量子投票协议,该协议通过随机选择信号加载的方式,充分利用量子信号测不确定性原理实现了分布式投票系统.并在此基础上分析可能遇到的攻击.双模压缩态的模间关联性保证了该方案的安全性. 关键词： 量子投票协议 双模压缩态 不确定性原理     

Secure deterministic communication scheme based on quantum remote state preparation

Based on the techniques of the quantum remote state preparation via a deterministic way, this paper proposes a quantum communication scheme to distribute the secret messages in two phases, i.e., the carrier state checking phase and the message state transmitting phase. In the first phase, the secret messages are encoded by the sender using a stabilizer quantum code and then transmitted to the receiver by implementing three CNOT gates. In the second phase, the communicators check the perfectness of the entanglement of the transmitted states. The messages can be distributed to the receiver even if some of the transmitted qubits are destroyed.