共查询到20条相似文献，搜索用时 31 毫秒
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In this paper the authors present the idea for reconstructing one-photon states. Reconstructing a quantum state means measuring the probability distribution P that allows one to write the density operator for the analysed state. The most commonly known approach for the quantum reconstruction is the quantum tomography. Our alternative method assumes that the analysed field is coupled with the reference field which is described by the parameters settled during a measurement. In the proposed gedankenexperiment the degree of linear polarisation (DOLP) of this combined beam is measured using a rotating linear polariser. We state that it is possible to obtain the P-function by changing the parameters of reference beams and by preparing the series of DOLP measurements. This series of data leads to the system of equations. The values of the P-function at chosen points are the unknowns of this system. This article focuses on the numerical algorithm for solving these equations. 相似文献
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《Journal of Modern Optics》2012,59(17):1458-1464
In a long-held preconception, photons play a central role in present-day quantum technologies. But what are sources producing photons one by one good for precisely? Well, in opposition to what many suggest, we show that single-photon sources are not helpful for point to point quantum key distribution because faint laser pulses do the job comfortably. However, there is no doubt about the usefulness of sources producing single photons for future quantum technologies. In particular, we show how single-photon sources could become the seed of a revolution in the framework of quantum communication, making the security of quantum key distribution device-independent or extending quantum communication over many hundreds of kilometers. Hopefully, these promising applications will provide a guideline for researchers to develop more and more efficient sources, producing narrowband, pure and indistinguishable photons at appropriate wavelengths. 相似文献
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This paper presents a novel algorithm for improved shape recovery using polarisation-based photometric stereo. The majority of previous research using photometric stereo involves 3D reconstruction using both the diffuse and specular components of light; however, this paper suggests the use of the specular component only as it is the only form of light that comes directly off the surface without subsurface scattering or interreflections. Experiments were carried out on both real and synthetic surfaces. Real images were obtained using a polarisation-based photometric stereo device while synthetic images were generated using PovRay® software. The results clearly demonstrate that the proposed method can extract three-dimensional (3D) surface information effectively even for concave surfaces with complex texture and surface reflectance. 相似文献
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超声诊断仪声强测量不确定度的评定 总被引：1，自引：0，他引：1
文章依据JJG639—1998国家规程的检定要求对医用超声诊断仪进行测量不确定度的评定，文中详细介绍了输出声强不确定度的来源、评定方法和自由度的计算。 相似文献
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为对电感耦合等离子体测定不锈钢食用器皿卫生指标实验方法的实用性作出评价，文章根据不确定度评估的通用方法对实验过程中不确定度的引入进行系统分析，在此基础上给出实验结果不确定度。 相似文献
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Yinhui Kan Sebastian K. H. Andersen Fei Ding Shailesh Kumar Changying Zhao Sergey I. Bozhevolnyi 《Advanced materials (Deerfield Beach, Fla.)》2020,32(16):1907832
Single photons carrying spin angular momentum (SAM), i.e., circularly polarized single photons generated typically by subjecting a quantum emitter (QE) to a strong magnetic field at low temperatures, are at the core of chiral quantum optics enabling nonreciprocal single-photon configurations and deterministic spin-photon interfaces. Here, a conceptually new approach to the room-temperature generation of SAM-coded single photons (SSPs) is described, which entails QE nonradiative coupling to surface plasmons being transformed, by interacting with an optical metasurface, into a collimated stream of SSPs with the designed handedness. Design, fabrication, and characterization of SSP sources, consisting of dielectric circular nanoridges with azimuthally varying widths deterministically fabricated on a dielectric-protected silver film around a nanodiamond containing a nitrogen-vacancy center, are reported. With properly engineered phases of QE-originated fields scattered by nanoridges, the outcoupled photons are characterized by a well-defined SAM (with the chirality >0.8) and high directionality (collection efficiency up to 92%). 相似文献
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文章对对接式半椭球顶卧式金属油罐测量结果不确定度进行了详细的分析和评定，评定方法符合JJFl059-1999和JJF1033-2001国家计量技术规范的要求。 相似文献
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Petr M. Anisimov 《Journal of Modern Optics》2018,65(11):1370-1377
AbstractClassical 1D X-ray Free Electron Laser (X-ray FEL) theory has stood the test of time by guiding FEL design and development prior to any full-scale analysis. Future X-ray FELs and inverse-Compton sources, where photon recoil approaches an electron energy spread value, push the classical theory to its limits of applicability. After substantial efforts by the community to find what those limits are, there is no universally agreed upon quantum approach to design and development of future X-ray sources. We offer a new approach to formulate the quantum theory for 1D X-ray FELs that has an obvious connection to the classical theory, which allows for immediate transfer of knowledge between the two regimes. We exploit this connection in order to draw quantum mechanical conclusions about the quantum nature of electrons and generated radiation in terms of FEL variables. 相似文献
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Multipartite entangled states are the key resource and play a crucial role in latest applications of quantum mechanics. We propose a scheme for the measurement of quantum state of multimode entangled field state trapped in multiple cavities. The scheme is based on the measurement of photon statistics of the displaced entangled field state in Ramsey type set-up. In this set-up, the atoms undergo a dispersive phase shift when they pass through the off-resonant entangled field in cavities. By measuring the internal states of the atoms, the photon statistics and the Wigner function can be reconstructed. 相似文献
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This study considers the design variable uncertainty in the actual manufacturing process for a product or structure and proposes a new interval optimization method based on tolerance design, which can provide not only an optimal design but also the allowable maximal manufacturing errors that the design can bear. The design variables' manufacturing errors are depicted using the interval method, and an interval optimization model for the structure is constructed. A dimensionless design tolerance index is defined to describe the overall uncertainty of all design variables, and by combining the nominal objective function, a deterministic two-objective optimization model is built. The possibility degree of interval is used to represent the reliability of the constraints under uncertainty, through which the model is transformed to a deterministic optimization problem. Three numerical examples are investigated to verify the effectiveness of the present method. 相似文献
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根据电偶极跃迁几率的定义和Wigner-Eckart定理,建立了计算铯原子与无缺陷金属表面间范德瓦尔斯（vdw）作用势的特定量子态的理论模型,并计算了铯原子基态、激发态各特定量子态C3的数值。 相似文献
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Combined with the dense coding mechanism and the bias-BB84 protocol, an efficient quantum key distribution protocol with dense coding on single photons (QDKD-SP) is proposed. Compared with the BB84 or bias-BB84 protocols based on single photons, our QDKD-SP protocol has a higher capacity without increasing the difficulty of its experiment implementation as each correlated photon can carry two bits of useful information. Compared with the quantum dense key distribution (QDKD) protocol based on entangled states, our protocol is more feasible as the preparation and the measurement of a single-photon quantum state is not difficult with current technology. In addition, our QDKD-SP protocol is theoretically proved to be secure against the intercept-resend attack. 相似文献
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We propose an optical protocol for quantum state sharing of superposed coherent state in terms optical elements. Our protocol can realize a near-complete quantum state sharing of a superposed coherent state with arbitrary coeficients. The realization of this protocol is appealing due to the fact that the quantum state of light is robust against the decoherence and photons are ideal carriers for transmitting quantum information over long distances. This protocol can also be generalized to the multiparty system. 相似文献
