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1.
Efficient entanglement concentration for arbitrary less-entangled NOON state assisted by single photons
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We put forward two efficient entanglement concentration protocols(ECPs) for arbitrary less-entangled NOON state.Both ECPs only require one pair of less-entangled NOON state and an auxiliary photon.In the first ECP,the auxiliary photon is shared by two parties,while in the second ECP,the auxiliary photon is only possessed by one party,which can increase the practical success probability by avoiding the transmission loss and simplify the operations.Moreover,both ECPs can be used repeatedly to get a high success probability.Based on the above features,our two ECPs,especially the second one,may be useful in the quantum information processing. 相似文献
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Consequent entanglement concentration of a less-entangled electronic cluster state with controlled-not gates
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We present a highly efficient entanglement concentration protocol (ECP) for a four-electron system in a less-entangled cluster state. In this ECP, we only require one pair of less-entangled electron cluster states and one ancillary electron to complete the task. With the help of the controlled-not (CNOT) gate, the concentrated maximally entangled state can be retained for further application with some success probability. On the other hand, the discarded items can be reused to obtain a high success probability. All the features make this ECP useful in the current quantum information field. 相似文献
4.
We present a scheme for locally concentrating a non-maximally entangled four-photon cluster state into a maximally-entangled four-photon cluster state. This scheme has a high success probability. The controlled-NOT (CNOT) gate is a crucial ingredient in this scheme, and we use a nearly deterministic CNOT gate, which is similar with that first introduced by Nemoto et al. (Phgs. Rev. Lett., 2004, 93: 250502). This CNOT gate has a simple structure and does not need the strong nonlinearity. 相似文献
5.
Efficient three-step entanglement concentration for an arbitrary four-photon cluster state
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We propose an entanglement concentration protocol to concentrate an arbitrary partially-entangled four-photon cluster state.As a pioneering three-step entanglement concentration scheme,our protocol only needs a single-photon resource to assist the concentration in each step,which makes this protocol more economical.With the help of the linear optical elements and weak cross-Kerr nonlinearity,one can obtain a maximally-entangled cluster state via local operations and classical communication.Moreover,the protocol can be iterated to obtain a higher success probability and is feasible under current experimental conditions. 相似文献
6.
提出一个隐形传送任意三原子纠缠W态的方案,在此方案中,选用由四个全同的二能级原子组成的cluster态作为量子信道.研究表明,接收者基于发送者的经典信息,借助于一个附加原子,实行联合幺正变换以及单原子幺正变换,可实现三原子W态的隐形传送.该方案不受外界热场和腔场耗散的影响,不需要贝尔态测量,成功实现传送的几率为1. 相似文献
7.
Probabilistic teleportation of an arbitrary GHZ-class state with a pure entangled two-particle quantum channel and its application in quantum state sharing 总被引:1,自引:0,他引:1
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This paper presents a scheme for probabilistic teleportation of an
arbitrary GHZ-class state with a pure entangled two-particle quantum
channel. The sender Alice first teleports the coefficients of the
unknown state to the receiver Bob, and then Bob reconstructs the
state with an auxiliary particle and some unitary operations if the
teleportation succeeds. This scheme has the advantage of
transmitting much less particles for teleporting an arbitrary
GHZ-class state than
others. Moreover, it discusses the application of this
scheme in quantum state sharing. 相似文献
8.
An entangled coherent state(ECS) is one type of entanglement, which is widely discussed in the application of quantum information processing(QIP). In this paper, we propose an entanglement concentration protocol(ECP) to distill the maximally entangled W-type ECS from the partially entangled W-type ECS. In the ECP, we adopt the balanced beam splitter(BS) to make the parity check measurement. Our ECP is quite different from the conventional ECPs. After performing the ECP, not only can we obtain the maximally entangled ECS with some success probability, but also we can increase the amplitude of the coherent state. Therefore, it is especially useful in long-distance quantum communication, if the photon loss is considered. 相似文献
9.
文章主要研究了CdSe量子点微腔结构,微腔结构包括上下分布式布拉格反射镜(DBR),中间的有源层为溶解在聚甲基丙烯酸甲酯(PMMA)中的CdSe胶体量子点.采用传递矩阵法模拟微腔的反射光谱,对实验测试曲线进行较好的拟合.通过测试微腔结构的光致荧光(PL)光谱,其半峰宽(FWHM)由未加入微腔的CdSe量子点样品的27.9 nm,减小到微腔结构的7.5 nm,在微腔中的量子点,由于腔模式的出现,其发光谱的品质因数增加了3.6倍,达到了荧光增强的效果.
关键词:
CdSe量子点
微腔效应
荧光增强 相似文献
10.
Symmetry and size effects on energy and entanglement of an exciton in coupled quantum dots
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We study theoretically the essential properties of an exciton in vertically coupled Gaussian quantum dots in the presence of an external magnetic field. The ground state energy of a heavy-hole exciton is split into four energy levels due to the Zeeman effect. For the symmetrical system, the entanglement entropy of the exciton state can reach a value of 1. However, for a system with broken symmetry, it is close to zero. Our results are in good agreement with previous studies. 相似文献
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We propose an efficient protocol for W polarization entangled state distribution over an arbitrary collective-noise channel with the help of the cross-Kerr nonlinearity. The entangled state in the frequency degree of freedom, which suffers little from the noise in an optical fiber, is used in the present protocol. The frequency entanglement can be transferred into polarization entanglement with the success probability of 100%. So, the three parities can share the maximally W polarization state with local operations and polarization independent wavelength division multiplexers which can erase distinguishability for frequency. 相似文献
14.
We study optical transmission properties of a combined system which is composed of a photonic crystal (PC) microcavity with low quality factor Q, a triple quantum dot (QD) embedded in cavity and two parallel waveguides. We demonstrate that low coupling strength (i.e., the weak coupling regime) between a cavity and a dot, by means of electron tunnel-induced coupling, can lead to a type of double-state controllable optical switching under the experimentally available parameter conditions. 相似文献
15.
经过激光辐照和高温退火加工能够生成多孔硅样品,在650—780 nm处检测到很强的光致荧光(PL)峰,并且有明显的钉扎和增强效应.实验表明,这种PL发光的强度与样品受辐照和退火的时间短密切相关.通过第一性原理模拟计算发现,样品表面用SiO 双键和Si—O—Si桥键钝化,能隙中会出现电子局域态.激光辐照和高温退火的时间长短决定了样品表面SiO双键和Si—O—Si桥键的密度,而该密度正是影响多孔硅量子点中电子局域态生成的关键.
关键词:
多孔硅量子点
硅氧钝化键
电子局域态 相似文献
16.
利用共生纠缠度研究了单模腔场内两个耦合量子点中激子的纠缠动力学行为.结果表明:无论腔场初始制备于奇相干态还是偶相干态,两个量子点间直接耦合作用均能减弱激子的纠缠度.在腔场初始为奇相干态时,激子的纠缠度随场模强度的增加而减小;偶相干态时,激子的纠缠度呈现一个转折变化.此外,也研究了单模腔场内平均光子数与激子准最大相干纠缠态的关联. 相似文献
17.
Very recently, a multiexcitonic quantum dot in an optical microcavity have been theoretically studied [Herbert Vincka, Boris
A. Rodriguez, and Augusto Gonzalez, Physica E, 2006, 35: 99–102]. However, due to the inevitable damping losses through the
microcavity, in this work, we will present a more precise and sound model in the Lindblad form master equation to investigate
the photonic properties of a single quantum dot (QD) in an optical microcavity system, in which the QD may confine the multiexcitons
and be in resonant interaction with a single photonic mode of an optical microcavity. The excitation energies, and the properties
of the emission photon from the QD microcavity are computed as functions of the exciton-photon coupling strength, detuning,
and pump rate. We further compare our results with their results, and find that the calculated intensity of the emitted photon
and the spectra crucially depend on the exciton-photon coupling strength g, the photon detuning, and the number of excitons in the QD. Finally, we will give a physical mechanism of the dressed-state
picture for the strong coupling between the single mode of an optical microcavity and the QD emitters to explain the details
of the emission photon spectra. Our study establishes useful guidelines for the experimental study of such multiexcitonic
quantum dot in an optical microcavity system.
相似文献
18.
量子纠缠是实现量子计算和量子通信的核心基础,本文提出了在金刚石氮-空位色心(NV centers)自旋系综与超导量子电路耦合的混合系统中实现两个分离量子节点之间纠缠的理论方案.在该混合系统中,把金刚石NV centers自旋系综和与之耦合的超导共面谐振器视为一个量子节点,两个量子节点之间通过一个空的超导共面谐振器连接.具有较长相干时间的NV centers自旋系综作为一个量子存储器,用于制备、存储和发送量子信息;易于外部操控的超导量子电路可执行量子逻辑门操作,快速调控量子信息.为了实现两个分离量子节点之间的纠缠,首先对系统的哈密顿量进行正则变换,将其等价为两个NV centers自旋系综与同一个超导共面谐振器之间的JC耦合;然后采用NV centers自旋-光子混合比特编码的方式,通过调节超导共面谐振器的谐振频率,精确控制体系演化时间,高保真度地实现了两个分离量子节点之间的量子纠缠.本方案还可以进一步扩展和集成,用于构建多节点纠缠的分布式量子网络. 相似文献
19.
We have investigated the problem of teleporting a three-particle entangled W state and we propose a scheme based on entanglement spapping to complete the teleportation.We also put forward a scheme for the teleportation of a general W state by using nonmaximally entangled quantum channels.The probability of success of the latter scheme is obtained. 相似文献
20.
Optimal entanglement concentration for three-photon W states with parity check measurement
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We present an efficient entanglement concentration protocol(ECP) for the less-entangled W state with some identical conventional polarized single photons.In the protocol,two of the parties say Alice and Charlie should perform the parity check measurements and they can ultimately obtain the maximally entangled W state with a certain success probability.Otherwise,they can obtain another less-entangled W state,which can be reconcentrated into the maximally entangled W state.By iterating this ECP,a high success probability can be achieved.This ECP may be an optimal one and it is useful in current quantum information processing. 相似文献