自由空间量子通信动态偏振补偿研究(英文)

In polarization-encoded free-space quantum communications, a transmitter on a satellite and a receiver in a ground station each have a respective polarization zero direction, by which they encode and decode every polarization quantum bit required for a quantum communication protocol. In order to complete the protocol, the ground-based receiver needs to track and compensate for the polarization zero direction of the satellite-based transmitter. Expressions satisfied by amplitudes of the s-polarization component and the p-polarization component are derived based on a two-mirror model, and a condition satisfied by the reflection coefficients of the two mirrors is given. A polarization tracking principle is analyzed for satellite-to-ground quantum communications, and quantum key encoding and decoding principles based on polarization tracking are given. A half-wave-plate-based dynamic polarization-basis compensation scheme is proposed in this paper, and this scheme is proved to be suitable for satellite-to-ground and intersatellite quantum communications.     

基于图的非二元非对称量子码构造(英文)

The theory of quantum error correcting codes is a primary tool for fighting decoherence and other quantum noise in quantum communication and quantum computation. Recently, the theory of quantum error correcting codes has developed rapidly and been extended to protect quantum information over asymmetric quantum channels, in which phase-shift and qubit-flip errors occur with different probabilities. In this paper, we generalize the construction of symmetric quantum codes via graphs (or matrices) to the asymmetric case, converting the construction of asymmetric quantum codes to finding matrices with some special properties. We also propose some asymmetric quantum Maximal Distance Separable (MDS) codes as examples constructed in this way.     

Increased radiative recombination of AlGaN-based deep ultraviolet laser diodes with convex quantum wells

An AlGaN-based deep ultraviolet laser diode with convex quantum wells structure is proposed. The advantage of using a convex quantum wells structure is that the radiation recombination is significantly improved. The improvement is attributed to the increase of the effective barrier height for electrons and the reduction of the effective barrier height for holes, which results in an increased hole injection efficiency and a decreased electron leakage into the p-type region. Particularly, comparisons with the convex quantum barriers structure and the reference structure show that the convex quantum wells structure has the best performance in all respects.     

Development of Hybrid ARQ Protocol for the Quantum Communication System on Stabilizer Codes

In this paper,we develop a novel hybrid automatic-repeat-request(ARQ)protocol for the quantum communication system using quantum stabilizer codes.The quantum information is encoded by stabilizer codes to against the channel noise.The twophoton entangled state is prepared for codeword secure transmission.Hybrid ARQ protocol rules the recognition and retransmission of error codewords.In this protocol,the property of quantum entangled state ensures the security of information,the theory of hybrid ARQ system improves the reliability of transmission,the theory of quantum stabilizer codes corrects the flipping errors of codewords.Finally,we verify the security and throughput efficiency of this protocol.     

INFORMATION FOR AUTHORS

SEMICONDUCTOR PHOTONICS AND TECHNOLOGY(SPAT)is published quarterly with thepurpose of providing the publication of original and significant contributions relating to photonic-light-wave components and applications,laser physics and systems,infrared physics and systems,and theirstechnologies．Publication notice time will be six months from the end of the month in which the contri-bution is accepted,provided the author responds immediately to all communications．Lengths of the let-@1     

Properties of a polaron in a quantum dot:a squeezed-state variational approach

The ground-state energy and the average number of virtual phonons around the electron in a parabolic quantum dot for the entire range of the electron-phonon coupling constant are obtained using the single-mode squeezed-state variational approach.The variational approach we applied is based on two successive canonical transformations and using a displaced-oscillator type unitary transformation to deal with the bilinear terms which are usually neglected.In order to study the relationship between the ground-state energy and the average number of virtual phonons around the electron of a polaron in a parabolic quantum dot with the electron-LO-phonon coupling constant and the confinement length,numerical calculations are carried out in the electron-LO-phonon strong-and weak-coupling regions.     

Magneto-polaron induced intersubband optical transition in a wide band gap Ⅱ–Ⅵ semiconductor quantum dot

Effects of LO-phonon contribution on the electronic and the optical properties are investigated in a Cd0:8Zn0:2Se/ZnSe quantum dot in the presence of magnetic field strength. The magneto-polaron induced hydrogenic binding energy as a function of dot radius in the wide band gap quantum dot is calculated. The oscillator strength and the spontaneous lifetime are studied taking into account the spatial confinement, magnetic field strength and the phonon contribution. Numerical calculations are carried out using variational formulism within the single band effective mass approximation. The optical properties are computed with the compact density matrix method. The magneto-polaron induced optical gain as a function of photon energy is observed. The results show that the optical telecommunication wavelength in the fiber optic communications can be achieved using CdSe/ZnSe semiconductors and it can be tuned with the proper applications of external perturbations.     

ANFIS-based approach to studying subthreshold behavior including the traps effect for nanoscale thin-film DG MOSFETs

A fuzzy framework based on an adaptive network fuzzy inference system(ANFIS) is proposed to evaluate the relative degradation of the basic subthreshold parameters due to hot-carrier effects for nanoscale thin-film double-gate(DG) MOSFETs.The effect of the channel length and thickness on the resulting degradation is addressed, and 2-D numerical simulations are used for the elaboration of the training database.Several membership function shapes are developed,and the best one in terms of accuracy is selected.The predicted results agree well with the 2-D numerical simulations and can be efficiently used to investigate the impact of the interface fixed charges and quantum confinement on nanoscale DG MOSFET subthreshold behavior.Therefore,the proposed ANFIS-based approach offers a simple and accurate technique to study nanoscale devices,including the hot-carrier and quantum effects.     

方形半导体量子线中光吸收的横向斯塔克效应

The ground and few excited states of the electrons confined in a square GaAs quantum wire(QW) subjected to an external transverse electric field are investigated using the finite difference method within the effective-mass approximation. When the transverse electric field is applied along a side of the square quantum wire, the calculation of the eigenstates of the quantum wire has an exactly solvable problem whose solutions involve the linear combinations of two independent Airy functions. Compared with the exact analytical results using Airy functions, the results obtained by the use of the finite difference method in terms of the eigenstates of the particle in the QW are in excellent agreement. Subsequently, it is considered that the eigenstates of the particle depend on the orientations of the electric field with respect to the center axis of the QW. It is interesting that the peak value of the energy is found for the field directed along the diagonal in the QW, which can lead to a large energy shift. Meanwhile, dependence of the optical absorption phenomenon in the square QW on the optical field and applied electric field is investigated. It is shown that the optical absorption spectrum depends highly upon the polarization of the optical field and the applied electric field intensities and orientations.     

A compact charge-based model to study the nanoscale undoped double gate MOSFETs for nanoelectronic circuit design using genetic algorithms

The analytical modeling of nanoscale devices is an important area of computer-aided design for fast and accurate nanoelectronic design and optimization.In the present paper,a new approach for modeling semiconductor devices,nanoscale double gate DG MOSFETs,by use of the gradual channel approximation(GC) approach and genetic algorithm optimization technique(GA) is presented.The proposed approach combines the universal optimization and fitting capability of GA and the cost-effective optimization concept of quantum correction,to achieve reliable,accurate and simple compact models for nanoelectronic circuit simulations.Our compact models give good predictions of the quantum capacitance,threshold voltage shift,quantum inversion charge density and drain current.These models have been verified with 2D self-consistent results from numerical calculations of the coupled Poisson-Schrodinger equations.The developed models can also be incorporated into nanoelectronic circuit simulators to study the nanoscale CMOS-based devices without impact on the computational time and data storage.     

量子信息理论与技术

阐述了量子计算、量子编码、量子通信及量子密码的基本思想与研究新进展,提出了量子信源编码的率失真概念,利用交织器处理量子部分消相干问题的思想及量子多址通信与量子信号阵列处理结合的想法。     

量子通信与量子计算

量子信息学是物理学目前研究的热门领域，它主要包括量子通信和量子计算，文章简要介绍了量子通信和量子计算的理论框架，包括量子纠缠、量子不可克隆定理、量子密钥分配、量子隐形传态、量子并行计算、Shor以及Grover的量子算法，并介绍该领域的研究进展。     

Chip-based quantum communications

Quantum communications aim to share encryption keys between the transmitters and receivers governed by the laws of quantum mechanics.Integrated quantum photonics offers significant advantages of dense integration,high stability and scalability,which enables a vital platform for the implementation of quantum information processing and quantum commu-nications.This article reviews recent experimental progress and advances in the development of integrated quantum photonic devices and systems for quantum communications and quantum networks.     

量子反馈控制研究进展

量子反馈控制理论将反馈的思想引入量子系统的主动控制中,已开始在量子光学、原子物理和量子信息学等领域发挥越来越重要的作用.考虑到各种反馈策略的差异性,综述了量子反馈控制理论的研究进展,分析和阐述了马尔可夫量子反馈、贝叶斯量子反馈、含时延非马尔可夫量子反馈和相干量子反馈,并对四种量子反馈策略进行了简单比较.     

量子通信的特色和局限性分析

利用量子纠缠粒子对的远程关联可以实现隐形传态,这是在经典物理现象中找不到的最奇妙的特性,它在量子通信中可能会扮演一个非常特殊的角色。但是利用隐形传态通信能否实现超光速通信、能否突破经典通信的距离和速率极限？通过从量子特性和通信系统工程角度对这些问题进行详细分析可知量子通信存在一些局限性,其在对潜通信和深空通信领域的应用前景有限,对量子通信系统的特色和局限性进行客观分析具有重要意义。     

量子通信网络发展概述

量子通信是基于量子力学原理的安全通信技术,能保证通信双方信息传输在理论上的绝对安全性。近年来,该项技术及其工程实现受到美国、欧盟、中国、日本等诸多国家和地区的重视。随着该技术实用化的推进,量子通信正在由点对点通信应用走向网络化应用,包括局域网和广域网应用。覆盖全球的广域量子通信网也在研发之中。详细分析了目前世界主要国家试行的量子通信网络,并简述了各国的量子通信卫星研发计划。     

量子密钥分发网方案的改进设计

量子密码术要走向实用化,必须实现多用户间的量子密钥分配.首先介绍了基于EPR对的E91量子密钥分发方案.利用该协议,我们在现有量子密钥分发网方案的基础上提出了一种实现多用户网络下任意多个用户之间的密钥分发方案,并融合波分复用技术对级联式环型量子密钥分发网方案进行了改进.     

相干位移操作辅助下的量子放大器研究

本文针对位移操作辅助下的量子线性放大器进行了研究.量子线性放大器可以提高量子态传输的保真度,提高量子通信抗干扰、抗损耗能力.本文针对目前量子线性放大器放大增益和放大成功概率低的问题,提出了相干位移增强型量子线性放大器,给出了位移操作提升量子线性放大器的机制,推导出放大增益得以进一步提高所需的位移操作的阈值,并结合态空间向光子数空间转化定理,在0-1光子数空间和多光子空间中同时验证了放大增益对位移量之间的依赖关系.     

量子力学发展综述

量子力学是对经典物理学在微观领域的一次革命，是对牛顿物理学的根本否定。量子力学是现代物理学基础之一，在低速、微观的现象范围内具有普遍适用的意义。论述了量子力学的发展以及与量子力学相关的物理概念，讨论了量子力学研究的主要内容。     

量子阱垂直腔面发射激光器及其微腔物理

根据发展历史的顺序,对量子阱垂直腔面发射激光器微腔物理进行了概述,其中包括垂直腔面发射激光器、腔量子电动力学和半导体微腔物理。给出半导体垂直腔面发射激光器及其微腔物理思想来源的详细图像。