共查询到20条相似文献,搜索用时 250 毫秒
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提出并验证了一种基于矢量叠加原理对输入射频信号进行差分编码的光子模数转换方案.该方案采用两路不同波长脉冲源通过一个相位调制器对输入射频信号进行调制,调制输出接入延时线干涉仪从而产生两路具有固定相位差的差分调制信号.利用矢量叠加模块对两路差分调制信号的强度进行不同程度的衰减和组合,从而获得系统量化所需的各路传递函数之间的相移量.该方案能够对输入射频信号实现差分编码,有效提高了系统的比特精度.同时该方案结构简单,只需要一个相位调制器,一个延时线干涉仪和一个矢量叠加模块即可构建.另外,各路传递函数之间的相移量是通过衰减两路差分调制信号的强度来实现,避免了传统光子模数转换方案中调制器对温度、环境敏感而引入的相位漂移问题.本文对4比特模数转换系统进行了原理性验证,实验结果证实了基于矢量叠加原理的光子模数转换方案的可行性. 相似文献
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自发参量下转换对应于一种非线性光学过程, 实验上作为一种标准方法, 人们利用自发参量下转换源产生纠缠光子对. 本文考虑由自发参量下转换源产生三对纠缠光子的情况. 通过使用由几组偏振光 束分束器、分束器和半波片等线性光学器件组成的量子线路演化三对光子, 给出了一个高效制备 包含偏振纠缠和空间纠缠的六光子超纠缠态方案. 因为方案中包含了参量下转换源产生三对纠缠光子 的所有可能情况, 所以本方案有很高的效率. 基于弱非线性介质构建了一个量子非破坏性测量装置, 用于区分光子在两指定的空间模中的两种分布情况. 特别地, 方案中可以通过合理约束在量子非破坏性测量过程中引入的非线性强度来达到实际实验所限定的数量级, 因此, 该方案易于在实验上实现. 相似文献
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单光子探测器量子效率绝对自身标定方案 总被引:1,自引:0,他引:1
参考已有的方案,提出了一种更简单的方案来实现单光子探测器量子效率的绝对自身标定。我们利用同轴线缆和数据采集卡代替已有方案中的符合测量电路和计数器,通过精确设定同轴线缆的长度,利用电脉冲在同轴线缆的短路终端反射回波的特性,对一个测量周期中单个脉冲和连续两个脉冲进行区分,用数据采集卡记录区分结果,分别得到探测器探测到两个孪生光子的计数和仅探测到其中任意一个光子的计数,从而算出单光子探测器的量子效率。此方案不需要其他任何的参考标准或者另一个探测器. 相似文献
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基于弱的交叉克尔效应和线性光学元件,利用光子偏振宇称门呈现了一个关于制备Cluster态的方案.本方案引入了交叉克尔非线性介质,采用了对相干探测模的非破坏测量,有效实现了光子与光子间的相互作用,进而获得所期望的光子纠缠态,同时可以提高制备的成功概率和制备态的保真度.通过本方案可以制备接近完美保真度的四光子偏振Cluster态,并具有接近1的成功概率.在本方案的基础上通过利用线性光学元件还可以获得3N+1个光子的偏振Cluster态. 相似文献
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In this paper a quantum dialogue scheme is proposed by using N batches of single
photons. The same secret message is encoded on each batch of single photons by the
sender with two different unitary operations, and then the N batches of single
photons are sent to the receiver. After eavesdropping check, the message is encoded
on the one remaining batch by the receiver. It is shown that the
intercept-and-resend attack and coupling auxiliary modes attack can be resisted more
efficiently, because the photons are sent only once in our quantum dialogue scheme. 相似文献
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邵瑞 《原子与分子物理学报》2008,25(6):1352-1356
我们提出一个方案通过极化光子的干涉来制备囚禁在相距很远的腔中的n原子GHZ类态。在该方案中,原子腔耦合强度小于腔衰减率。因此对腔的品质因子的要求大大降低了,而且,该方案的保真度不受探测器效率和原子自发衰变的影响。
中文关键词:纠缠制备;GHZ类态;腔QED 相似文献
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A scheme is proposed for generating maximally entangled states for two cavity modes, with each containing no more than two photons. In the scheme a single atom is sent through two resonant single-mode cavities. Based on the presently available techniques, our scheme might be experimentally realizable. 相似文献
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ZHOU Jian DONG Ping CAO Zhuo-Liang 《理论物理通讯》2007,48(5):847-850
We present a scheme for teleportation of multi-ionic GHZ states and arbitrary bipartite ionic state only by single-qubit measurements via linear optical elements. In our scheme, we avoid the difficulty of joint measurement and synchronizing the arrival time of the two scattered photons, which are faced by previous schemes. So our scheme can be realized easily within current experimental technology. 相似文献
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我们采用周期极化KTP晶体为非线性介质,通过光学参量振荡器运转于阈值以下的简并参量振荡过程,产生了单模正交压缩真空态光场,在泵浦功率为123mW,Local光功率为842uW,晶体温度为32.1摄氏度时我们使用平衡零拍探测法测得输出场噪声功率低于散粒噪声基准3.41dB。 相似文献
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Based on adiabatic passage, we propose a scheme for implementing the quantum
transfer of an unknown atomic state. In our scheme, we utilize photons for
ideal quantum transmission between two cavities with the successful
probability being about 1. Meanwhile, the scheme is robust against the
effects of atomic spontaneous emission. It may be useful for transferring
quantum information among spatially distant atoms. 相似文献
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Qubits are realized as polarization state of photons or as superpositions of the spin states of electrons. In this paper we propose a scheme to probabilistically teleport an unknown arbitrary two-qubit state using a non-maximally entangled GHZ-like state and a non-maximally Bell state simultaneously as quantum channels. We also discuss the success probability of our scheme. We perform POVM in the protocol which is operationally advantageous. In our scheme we show that the non-maximal quantum resources perform better than maximal resources. 相似文献
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Bin Gu Fei Xu Liuguan Ding Yanan Zhang 《International Journal of Theoretical Physics》2012,51(11):3559-3566
We presents a novel scheme for high-capacity three-party quantum secret sharing (QSS) with the hyperentanglement in both the polarization and the spatial-mode degrees of freedom of photon pairs. The boss Alice need only prepare a sequence of photon pairs and some decoy photons. Her two agents measure their photons received from the boss Alice with two bases by choosing two unsymmetrical probabilities. The present QSS scheme has a high capacity as each pair can carry 2 bits of information, several times as other QSS schemes. Moreover, our setups with linear optical elements show that our QSS scheme does not increase the difficulty of its implementation in experiment and it is feasible with current techniques. 相似文献
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The maximally entanglement will become less-entangled state because of the effects of decoherence. However, maximally entangled states are usually important for most of the quantum information processing protocols. So we propose a practical entanglement concentration protocol of an arbitrary four-photon less-entangled state assisted with single photons, which greatly reduces the difficulty of the experimental realization. In our scheme, we only employ three steps, a four-photon cluster state can be acquired with a certain probability by three affiliated photons. The protocol adopts the linear optical elements and weak cross-Kerr media, which make the scheme more simple and feasible in the experiment. 相似文献