共查询到20条相似文献,搜索用时 62 毫秒
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为研究圆柱曲面的单光子量子雷达散射截面与经典雷达散射截面相比存在的具体优势,引入光子波函数,将引起量子干涉的距离矢量进行分解,通过圆柱曲面的曲面积分推导得到了单基地单光子下的圆柱曲面量子雷达散射截面的封闭表达式.分析了不同电尺寸的圆柱曲面长度和曲率半径的影响,对比了圆柱曲面量子雷达散射截面与经典雷达散射截面的封闭表达式.封闭表达式的分析和仿真结果都表明,圆柱曲面长度的电尺寸决定量子雷达散射截面的旁瓣数,曲率半径的电尺寸决定了量子雷达散射截面曲线的包络,量子雷达散射截面的整体强度与曲率半径的电尺寸呈线性关系.圆柱曲面的量子雷达散射截面与经典雷达散射截面相比具有旁瓣增强的优势,有利于隐身目标的探测. 相似文献
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针对导弹目标量子雷达散射截面的计算问题,用锥柱复合模型模拟导弹目标几何结构,引入单光子波动方程,推导和改进量子雷达散射截面表达式.通过干涉分析镜面上原子与光子的相互作用,在检测点测量光子被目标原子散射后的强度,得到锥柱复合目标量子雷达散射截面公式.仿真结果表明:在不同入射角条件下,单光子量子雷达散射截面主瓣峰值高于经典雷达散射截面,而量子雷达散射截面旁瓣峰值低于经典雷达散射截面;随着波长减小,量子雷达散射截面逐渐降低,入射角对量子雷达散射截面无影响.表明量子雷达对小目标具有很高的探测识别能力,分辨率能够达到纳米级,为导弹目标识别提供了依据. 相似文献
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非理想的纠缠资源和非标准的量子隐形传态操作导致非理想的量子态传输.本文从Nielsen-Caves理论出发,导出了非理想的量子隐形传态过程对应的量子信道的明显表达式.这给我们提供了对量子隐形传态的新认识,即量子隐形传态过程可等效地看作量子态依次通过三个量子信道的过程,这三个信道分别对应于发送者的测量、纠缠态和接收者的操作.特别地,我们建立了纠缠态与量子信道之间的一一对应关系,即一个纠缠态对应于这样一个量子信道,如果把描述该量子信道的Kraus算符用Pauli算符展开,则得到的参数矩阵就是该纠缠态的密度算符在Bell基下的矩阵.我们还导出了量子隐形传态保真度的明显表达式.我们的结果解析地揭示了输出态和保真度对纠缠资源和量子隐形传态操作的依赖关系. 相似文献
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量子保密通信包括量子密钥分发、量子安全直接通信和量子秘密共享等主要形式.在量子密钥分发和秘密共享中,传输的是随机数而不是信息,要再经过一次经典通信才能完成信息的传输.在量子信道直接传输信息的量子通信形式是量子安全直接通信.基于量子隐形传态的量子通信(简称量子隐形传态通信)是否属于量子安全直接通信尚需解释.构造了一个量子隐形传态通信方案,给出了具体的操作步骤.与一般的量子隐形传态不同,量子隐形传态通信所传输的量子态是计算基矢态,大大简化了贝尔基测量和单粒子操作.分析结果表明,量子隐形传态通信等价于包含了全用型量子密钥分发和经典通信的复合过程,不是量子安全直接通信,其传输受到中间介质和距离的影响,所以不比量子密钥分发更有优势.将该方案与量子密钥分发、量子安全直接通信和经典一次性便笺密码方案进行对比,通过几个通信参数的比较给出各个方案的特点,还特别讨论了各方案在空间量子通信方面的特点. 相似文献
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热库诱导的两比特量子纠缠与量子关联 总被引:1,自引:0,他引:1
对比研究了处于热库中的两量子比特的量子纠缠和量子关联随时间的演化。数值模拟的结果表明,尽管热库几乎总能诱导两量子比特的量子纠缠与量子关联,但二者的动力学演化并不完全相同。在与热库的相互作用中,两比特初始形成量子纠缠,随后纠缠逐渐消失,两比特形成纠缠以外的量子关联并得到维持。由此看出,相比于量子纠缠,量子关联对消相干的影响表现得更为稳健。 相似文献
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在量子散射框架下,对真实激光场引进多光子相互作用准静态过程模型,考虑束缚-自由跃迁中电磁场的规范一致性及电子与激光场长程相互作用的极限,研究激光场对量子散射过程中三重微分散射截面的影响.多数共面非对称情况下激光场对三重微分散射截面有提升作用,此外靶原子处于激发态时binary峰出现分裂,激光场对三重微分散射截面也有放大作用. 相似文献
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《Physics letters. A》2001,284(6):275-278
Eikonal method is applied to investigate the quantum effects on elastic electron–ion collisions in a two-component plasma. An effective Kelbg potential model taking into account the classical effect as well as the quantum-mechanical effect is applied to describe the electron–ion interactions in a two-component plasma. The impact parameter method is applied to represent the path of the projectile electron in order to investigate the variation of the eikonal cross section as a function of the impact parameter, thermal de Broglie wavelength, and projectile energy. In the second-order eikonal approximation, the quantum effects significantly reduce the elastic electron–ion scattering cross section. It is also found that the second-order eikonal phase is caused by the pure quantum mechanical effects. 相似文献
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《Solid State Communications》1987,63(2):123-126
Electron scattering by neutral acceptors has been studied through far infrared (λ=172 μm) cyclotron resonance on p-GaAs at 4.2 K. It is found that (1) The inverse relaxation time is considerably smaller in the quantum limit than that predicted by D.C. transport theory in the absence of a magnetic field. (2) The same increase linearly with neutral acceptor concentration. (3) The electron momentum transfer cross section by neutral acceptor is by more than an order of magnitude smaller than that by neutral donor even in the quantum limit. 相似文献
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This review contains theoretical study of resonant quantum electrodynamics processes in a pulsed laser field. The approximation is examined when the pulse width is considerably greater than the characteristic time of wave oscillations. The lepton??s interaction with the Coulomb potential of a nucleus and each other is considered in the Born approximation. It is demonstrated that the resonant differential cross section of a process in a pulsed light fields may considerably exceed the corresponding cross section in an absence of a laser field. Results obtained may be experimentally verified by the scientific facilities at the SLAC National Accelerator Laboratory and FAIR (Facility for Antiproton and Ion Research, Darmstadt, Germany) project. 相似文献
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为了研究尘埃等离子体中带电尘埃的粒子半径、粒子浓度和带电荷数对量子通信性能的影响,首先根据Mie散射理论得到单个带电尘埃粒子的光散射截面;然后通过粒子浓度求出总的消光截面,得出链路衰减的数学模型,提出了带电粒子特性与量子纠缠度的关系;针对退极化信道,当单个尘埃粒子所吸附带电粒子的个数为50时,给出了尘埃粒子半径、粒子浓度与信道容量和量子误码率的定量关系.仿真结果表明,当量子信号的传输距离为10km时,尘埃粒子浓度从1×10~(10) m~(-3)增加到10×10~(10) m~(-3),信道容量从0.6726降低到0.1075;尘埃粒子半径从0.1μm增加到10μm时,量子误码率由1.334×10~(-3)增加到5.309×10~(-3).由此可见,尘埃等离子体中带电尘埃粒子的半径和浓度对量子卫星通信性能有显著的影响.因此,为确保量子通信的可靠性,应根据所探测到的等离子体环境的状况,调整卫星通信系统的各项指标参数. 相似文献
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Technical Physics - Several parameters (cross section, reaction rate, etc.) of various processes in laser, atomic, and chemical physics are calculated using quantum scattering theory for a system... 相似文献
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Zhenni Li Chang-shui Yu Shuxue Ding Zunyi Tang 《International Journal of Theoretical Physics》2013,52(10):3676-3682
We study a scheme that an auxiliary qubit is introduced for probing the information of the given bipartite quantum state, while the correlations of the probed quantum state and even the probed state itself are not disturbed after the probing, which means nondestructive probing. We find that, in order to guarantee the invariance of the correlations of the probed state, neither quantum entanglement nor quantum discord between the auxiliary qubit and the probed states can be present. This could make us reconsider the role of quantum correlation in some quantum information processing tasks. 相似文献
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Won-Seok Chang 《Physics letters. A》2007,372(1):52-55
The quantum effects on the polarization bremsstrahlung emission due to the low-energy electron-atom collisions are investigated in partially ionized dense hydrogen plasmas. The impact parameter analysis is employed to describe the motion of the projectile electron in order to investigate the variation of the bremsstrahlung emission spectrum as a function of the impact parameter, de Broglie wave length, Debye length, and radiation photon energy. The results show that the quantum effects strongly suppress the polarization bremsstarhlung emission. It is also found that the polarization bremsstarhlung emission cross section shows the maximum value at the position of the Bohr radius. It is interesting to note that the quantum effects are found to be more important than the screening effects in the polarization bremsstarhlung emission. 相似文献
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Hans Laue 《Foundations of Physics》1981,11(1-2):37-46
The formula for the differential scattering cross section in quantum mechanics is derived without the usual assumption that the square of the -function is a position probability density for particles. It is argued that position, like time, may be basically a macroscopic parameter rather than a random variable for microparticles.This research was partly supported by a grant from the NSERC. 相似文献
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Vlatko Vedral 《Foundations of Physics》2010,40(8):1141-1154
We discuss two qualities of quantum systems: various correlations existing between their subsystems and the distinguishability
of different quantum states. This is then applied to analysing quantum information processing. While quantum correlations,
or entanglement, are clearly of paramount importance for efficient pure state manipulations, mixed states present a much richer
arena and reveal a more subtle interplay between correlations and distinguishability. The current work explores a number of
issues related with identifying the important ingredients needed for quantum information processing. We discuss the Deutsch-Jozsa
algorithm, the Shor algorithm, the Grover algorithm and the power of a single qubit class of algorithms. In the latter, a
quantity called discord is seen to be more important than entanglement. One section is dedicated to cluster states where entanglement
is crucial, but its precise role is highly counter-intuitive. Here we see that the notion of distinguishability becomes a
more useful concept. 相似文献