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Optical switch fabric plays an important role in building multiple-user optical quantum communication networks.Owing to its self-routing property and low complexity, a banyan network is widely used for building switch fabric. While,there is no efficient way to remove internal blocking in a banyan network in a classical way, quantum state fusion, by which the two-dimensional internal quantum states of two photons could be combined into a four-dimensional internal state of a single photon, makes it possible to solve this problem. In this paper, we convert the output mode of quantum state fusion from spatial-polarization mode into time-polarization mode. By combining modified quantum state fusion and quantum state fission with quantum Fredkin gate, we propose a practical scheme to build an optical quantum switch unit which is block free. The scheme can be extended to building more complex units, four of which are shown in this paper. 相似文献
164.
Since the difficulty in preparing the equal superposition state of amplitude is 1/√N, we construct a quantile transform of quantum Fourier transform (QFT) over ZN based on the elementary transforms, such as Hadamard transform and Pauli transform. The QFT over Z_N can then be realized by the quantile transform, and used to further design its quantum circuit and analyze the requirements for the quantum register and quantum gates. However, the transform needs considerable quantum computational resources and it is difficult to construct a high-dimensional quantum register. Hence, we investigate the design of t-bit quantile transform, and introduce the definition of t-bit semiclassical QFT over Z_N. According to probability amplitude, we prove that the transform can be used to realize QFT over ZN and further design its quantum circuit. For this transform, the requirements for the quantum register, the one-qubit gate, and two-qubit gate reduce obviously when compared with those for the QFT over Z_N. 相似文献
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The construction of the China Spallation Neutron Source (CSNS) has been initiated at Dongguan,Guangdong,China.In spallation neutron sources the target station monolith is contaminated by a large number of fast neutrons whose energies can be as large as those of the protons of the proton beam directed towards the tungsten target.A detailed radiation transport analysis of the target station monolith is important for the construction of the CSNS.The analysis is performed using the coupled Monte Carlo and multi-dimensional discrete ordinates method.Successful elimination of the primary ray effects via the two-dimensional uncollided flux and first collision source methodology is also illustrated.The dose at the edge of the monolith is calculated.The results demonstrate that the doses received by the hall staff members are below the required standard limit. 相似文献
167.
自旋模型在实现量子信息处理中起着很重要的作用.将自旋之间的海森堡相互作用作为最基本量子比特之间的相互作用,将会使量子比特之间产生量子纠缠;同时忽略掉自旋之间相互作用的各向异性可直接用来实现(swap)n量子门,再配以单量子比特旋转门,可构成完备的量子计算基本门.事实上,各向异性相互作用是存在于任何固态材料中的,其对实现量子逻辑门的影响很值得研究.本文讨论了在非均匀外场下XYZ模型的双量子比特swap门的实现问题,给出非均匀外场以及各向异性相互作用导致的swap门操作的误差. 相似文献
168.
Fabrication of Pentacene Thin-Film Transistors with Patterned Polyimide Photoresist as Gate Dielectrics and Research of Their Degradation
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Pentacene organic thin-film transistors using commercial photoresist as gate dielectrics were fabricated. The photoresist was spin-coated and directly patterned by photolithography. As a result, the fabrication processes were greatly reduced. With the characteristics of the transistors measured, the degradation of the transistors was investigated. In the search for the factors causing degradation, a transistor using poly(methyl methacrylate) as the gate dielectric was also fabricated. It is regarded that the degradation is caused by the changes at the interface between photoresist and pentacene film. 相似文献
169.