共查询到20条相似文献,搜索用时 31 毫秒
1.
We propose a quantum teleportation scheme for tripartite entangled coherent state (ECS) with continuous variable. Our scheme is feasible and economical in the sense that we need only linear optical devices such as beam splitters, phase shifters and photon detectors and employ three bipartite maximally ECSs as quantum channels. We also generalize the tripartite scheme into multipartite ease and calculate the minimum average fidelity for the schemes in tripartite and multipartite cases. 相似文献
2.
We demonstrate how to perform quantum phase gate with cavity QED system in decoherence-free subspace by using only linear optics elements and photon detectors. The qubits are encoded in the singlet state of the atoms in cavities among spatially separated nodes, and the quantum interference of polarized photons decayed from the optical cavities is used to realized the desired quantum operation among distant nodes. In comparison with previous schemes, the distinct advantage is that the gate fidelity could not only resist collective noises, but also immune from atomic spontaneous emission, cavity decay, and imperfection of the photodetectors. We also discuss the experimental feasibility of our scheme. 相似文献
3.
Y. B. Sheng F. G. Deng B. K. Zhao T. J. Wang H. Y. Zhou 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(1):235-242
We present a scheme for multipartite entanglement purification of
quantum systems in a Greenberger-Horne-Zeilinger state with quantum
nondemolition detectors (QNDs). This scheme does not require the
controlled-not gates which cannot be implemented perfectly with
linear optical elements at present, but QNDs based on cross-Kerr
nonlinearities. It works with two steps, i.e., the bit-flipping
error correction and the phase-flipping error correction. These two
steps can be iterated perfectly with parity checks and simple
single-photon measurements. This scheme does not require the parties
to possess sophisticated single photon detectors. These features
maybe make this scheme more efficient and feasible than others in
practical applications. 相似文献
4.
In this paper, we present a linear optical scheme for optimal
unambiguous discrimination among nonorthogonal quantum states in
terms of the multiple-rail and polarization representation of a
single photon. In our scheme, discriminated quantum states are
expressed by using the spatial degree of freedom of a single photon
while the polarization degree of freedom of the single photon is
used to act as an auxiliary qubit. The optical components used in
our scheme are only passive linear optical elements such as
polarizing beam splitters, wave plates, polarizers, single photon
detectors, and single photon source. 相似文献
5.
We propose feasible experimental schemes for preparing all
five-photon graph states. Our schemes require only linear optical
elements, photon detectors and post-selection, which are available
in current experiment so that these schemes are within the reach of
the current technology. 相似文献
6.
We propose a simple experimental scheme in which an unknown two-qubit state
is faithfully and deterministically teleported from Alice to Bob. The scheme
is constructed with four photons from parametric down conversion, linear
optical elements, and conventional photon detectors, all of which are
available in current technology. It is shown that the probability of
successful teleportation ideally reaches 100% based on single-photon
two-qubit-assisted Bell-state measurement, which can distinguish all
four Bell-states simultaneously via conventional photon detectors. By
generalizing the scheme, the teleportation of an unknown multi-qubit system
can also be realized. 相似文献
7.
We propose two schemes for preparing four-photon cluster state through
cross-Kerr nonlinearity. Two coherent fields interact when they enter a
nonlinear Kerr medium. If the interaction time is chosen appropriately in each Kerr medium, four-photon cluster state can be generated based on the results of two homodyne detectors in the first scheme. These schemes only use Kerr medium and homodyne measurements on coherent light fields, which can be efficiently made in quantum optical laboratories. In addition, weak cross-Kerr
nonlinearity is sufficient. All of the properties make these schemes
feasible in experiments. 相似文献
8.
We present an optical scheme to almost completely teleport a bipartite entangled coherent state using a four-partite cluster-type entangled coherent state as quantum channel. The scheme is based on optical elements such as beam splitters, phase shifters, and photon detectors. We also obtain the average fidelity of the teleportation process. It is shown that the average fidelity is quite close to unity if the mean photon number of the coherent stateis not too small. 相似文献
9.
We present a linear optical scheme for achieving a unity fidelity teleportation of a two-particle four- component squeezed vacuum state using two entangled squeezed vacuum states as quantum channel. The devices used are beam splitters and ideal photon detectors capable of distinguishing between odd and even photon numbers. Moreover, we also obtain the success probability of the teleportation scheme. 相似文献
10.
H. F. Wang S. Zhang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(3):359-363
We propose a simple experimental scheme to prepare a type of
four-photon entangled state |χ〉 that has many interesting
entanglement properties and possible applications in quantum
information processing with a certain success probability. The
proposed setup involves only simple linear optical devices, a
single-photon polarization state, three pairs of two-photon
polarization entangled states, and the conventional photon detectors
that cannot distinguish a single photon from two or more photons,
which greatly simplify the experimental realization of the scheme. 相似文献
11.
We report a practical non-postselection entanglement concentration scheme in which a maximally entangled Bell-state photon pair is produced from two pairs of partially (or non-maximally) entangled photons. Since this scheme is built only upon linear optical elements and does not require photon-number resolving detectors, it has immediate applications in experimental implementations of various quantum information protocols which require two-photon Bell-states. 相似文献
12.
测量设备无关量子密钥分发系统可以免疫任何针对探测器边信道的攻击, 并进一步结合诱惑态方法规避了准单光子源引入的实际安全性问题. 目前实验中一般采用弱相干光源, 但是该光源含有一定比例的空脉冲和多光子脉冲. 本文针对弱相干光源的具体特性, 采用量子力学的描述, 将各个器件进行量子化处理, 并同时考虑探测器的具体性能参数的影响, 分别给出了通信双方各自发送的脉冲含有特定光子数时产生的成功贝尔态和错误贝尔态的概率公式, 从理论上对相位编码和偏振编码测量设备无关量子密钥分发系统的误码率进行了定量分析, 分别推导并模拟了通信双方采用的平均光子数对称和不对称时误码率随传输距离的变化情况, 结果表明在偏振编码Z基中, 多光子脉冲不会引起误码; 在偏振编码X基和相位编码中, 受多光子影响, 产生的误码率较大. 对于不同的编码方式, 误码率均随传输距离的增加有不同程度的升高, 长距离传输时, 平均光子数越小, 产生的误码率越大; 在偏振编码X基和相位编码的短距离传输中, 相对于对称, 通信双方采用的平均光子数不对称时产生的误码率较大. 相似文献
13.
An experimental scheme is proposed for faithful teleportation of a unknown optical cat-state via attenuated quantum channel due to energy loss or photon absorption during the process of entanglement sharing. The scheme is probabilistic, yet conclusive, and the effective classical communication costs just Log23 bits, instead of five bits which are necessary for full record of the measurement outcome. The scheme uses only threshold (i.e., yes/no) detectors so that exact photon counting is not needed. However, it requires application of a nonlinear element called cross-phase modulator. Feasibility of the scheme is also discussed with respect to EIT-based modern techniques. 相似文献
14.
Heralded linear optical quantum Fredkin gate based on one auxiliary qubit and one single photon detector 下载免费PDF全文
Linear optical quantum Fredkin gate can be applied to quantum computing and quantum multi-user communication networks. In the existing linear optical scheme, two single photon detectors (SPDs) are used to herald the success of the quantum Fredkin gate while they have no photon count. But analysis results show that for non-perfect SPD, the lower the detector efficiency, the higher the heralded success rate by this scheme is. We propose an improved linear optical quantum Fredkin gate by designing a new heralding scheme with an auxiliary qubit and only one SPD, in which the higher the detection efficiency of the heralding detector, the higher the success rate of the gate is. The new heralding scheme can also work efficiently under a non-ideal single photon source. Based on this quantum Fredkin gate, large-scale quantum switching networks can be built. As an example, a quantum Bene~ network is shown in which only one SPD is used. 相似文献
15.
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
16.
Yan Xia Si-Yang Hao Yun-Jiao Dong Jie Song 《Applied physics. B, Lasers and optics》2013,110(4):551-561
Schemes to generate Greenberger–Horne–Zeilinger and W maximally entangled states of distant photons with the help of cross-Kerr nonlinearity and parity-check measurement are proposed in this paper. The schemes are based on optical elements, single polarization photons, cross-Kerr nonlinearity, and the conventional photon detectors, which are feasible with existing experimental technology. The schemes are quite different a higher success probability, without the resorting to collective unitary evolution. All these advantages make present schemes more efficient and more convenient than others in the applications in quantum communication. 相似文献
17.
An optical scheme for probabilistic teleporting entangled squeezed vacuum states (SVS) is proposed. In this scheme, the teieported state is a bipartite entangled SVS, and the quantum channel is a tripartite entangled SVS. The process of the teleportation is achieved by using a 50/50 symmetric beamsplitter and photon detectors with the help of classical information. 相似文献
18.
We present a scheme for linear optical quantum computation that is highly robust to imperfect single photon sources and inefficient detectors. In particular we show that if the product of the detector efficiency with the source efficiency is greater than 2/3, then efficient linear optical quantum computation is possible. This high threshold is achieved within the cluster state paradigm for quantum computation. 相似文献
19.
We propose a scheme to effectively generate a four-photon path-entangled number state [the NOON state i.e. 1/√2(|N,0〉 + |0, N〉)] for the demonstration of four-photon de Broglie wavelength. Our scheme rcquires only linear optical elements, photon detectors and post-selections which are all within the reach of current technology. 相似文献
20.
Scheme for purifying a general mixed entangled state and its linear optical implementation 下载免费PDF全文
《中国物理 B》2015,(10)
We propose a scheme for purification of a general mixed entangled state. In this scheme, we start from a large number of general mixed entangled states and end up, after local operation and classical communication, with a smaller number of Bell diagonal states with higher entanglement. In particular, the scheme can purify one maximally entangled state from two entangled pairs prepared in a class of mixed entangled state. Furthermore we propose a linear optical implementation of the present scheme with polarization beam splitters and photon detectors. 相似文献