共查询到20条相似文献，搜索用时 22 毫秒
1.
In this paper, a novel quantum steganography protocol based on Brown entangled states is proposed. The new protocol adopts the CNOT operation to achieve the transmission of secret information by the best use of the characteristics of entangled states. Comparing with the previous quantum steganography algorithms, the new protocol focuses on its anti-noise capability for the phase-flip noise, which proved its good security resisting on quantum noise. Furthermore, the covert communication of secret information in the quantum secure direct communication channel would not affect the normal information transmission process due to the new protocol’s good imperceptibility. If the number of Brown states transmitted in carrier protocol is many enough, the imperceptibility of the secret channel can be further enhanced. In aspect of capacity, the new protocol can further expand its capacity by combining with other quantum steganography protocols. Due to that the proposed protocol does not require the participation of the classic channel when it implements the transmission of secret information, any additional information leakage will not be caused for the new algorithm with good security. The detailed theoretical analysis proves that the new protocol can own good performance on imperceptibility, capacity and security. 相似文献
2.
Zhuo-Liang Cao 《Journal of Modern Optics》2013,60(6):907-919
We propose a linear optical scheme for the transfer of unknown ionic states, the entanglement concentration for nonmaximally entangled states for ions via entanglement swapping and the remote preparation for ionic entangled states. The joint Bell state measurement needed in the previous schemes is not needed in the current scheme, i.e. the joint Bell state measurement has been converted into the product of separate measurements on single ions and photons. In addition, the current scheme can realize the quantum information processes for ions by using linear optical elements, which simplify the implementation of quantum information processing for ions. 相似文献
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In this work, we propose a new simple entanglement measurement scheme, which can be utilized to take a measurement for the bright EPR beams generated by a nondegenerate optical parametric amplifier. Owing to the output signal and idler modes being frequency degenerate and in phase, one need not take a measurement for the signal and idler modes, respectively. By virtue of a quarter-wave plate and a half-wave plate, and then inserting a polarizing beam splitter, one can realize the measurements of the correlated phase quadratures and anti-correlated amplitude quadratures, simultaneously. Therefore, phase-locking and local oscillators are avoided. 相似文献
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The controlled quantum secure direct communication (CQSDC) with authentication protocol based on four particle cluster states via quantum one-time pad and local unitary operations is cryptanalyzed. It is found that there are some serious security issues in this protocol. An eavesdropper (Eve) can eavesdrop on some information of the identity strings of the receiver and the controller without being detected by the selective-CNOT-operation (SCNO) attack. By the same attack, Eve can also steal some information of the secret message that the sender transmits. In addition, the receiver can take the same kind of attack to eavesdrop on some information of the secret message out of the control of the controller. This means that the requirements of CQSDC are not satisfied. At last, we improve the original CQSDC protocol to a secure one. 相似文献
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Yan Chang Shibin Zhang Lili Yan Guihua Han Haiquan Song Yan Zhang Xueyang Li Qirun Wang 《计算机、材料和连续体（英文）》2019,59(3):1005-1014
Quantum authorization management (QAM) is the quantum scheme for privilege management infrastructure (PMI) problem. Privilege management (authorization management) includes authentication and authorization. Authentication is to verify a user’s identity. Authorization is the process of verifying that a authenticated user has the authority to perform a operation, which is more fine-grained. In most classical schemes, the authority management center (AMC) manages the resources permissions for all network nodes within the jurisdiction. However, the existence of AMC may be the weakest link of the whole scheme. In this paper, a protocol for QAM without AMC is proposed based on entanglement swapping. In this protocol, Bob (the owner of resources) authenticates the legality of Alice (the user) and then shares the right key for the resources with Alice. Compared with the other existed QAM protocols, this protocol not only implements authentication, but also authorizes the user permissions to access certain resources or carry out certain actions. The authority division is extended to fin-grained rights division. The security is analyzed from the four aspects: the outsider’s attack, the user’s attack, authentication and comparison with the other two QAM protocols. 相似文献
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Quantum secure direct communication (QSDC) can transmit secret messages directly from one user to another without first establishing a shared secret key, which is different from quantum key distribution. In this paper, we propose a novel quantum secure direct communication protocol based on signal photons and Bell states. Before the execution of the proposed protocol, two participants Alice and Bob exchange their correspondingidentity IDA and IDB through quantum key distribution and keep them secret, respectively.Then the message sender, Alice, encodes each secret message bit into two single photons(| 01〉or|10〉) or a Bell state , and composes an ordered secret message sequence. To insure the security of communication,Alice also prepares the decoy photons and inserts them into secret message sequence on the basis of the values of IDA and IDB. By the secret identity IDA and IDB, both sides of the communication can check eavesdropping and identify each other. The proposed protocol not only completes secure direct communication, but also realizes the mutual authentication. The security analysis of the proposed protocol is presented in the paper. The analysis results show that this protocol is secure against some common attacks, and no secret message leaks even if the messages are broken. Compared with the two-wayQSDC protocols, the presented protocol is a one-way quantum communication protocolwhich has the immunity to Trojan horse attack. Furthermore, our proposed protocol can be realized without quantum memory. 相似文献
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Quantum mechanics shows superiority than classical mechanics in many aspects and quantum entanglement plays an essential role in information processing and some computational tasks such as quantum teleportation (QT). QT was proposed to transmit the unknown states, in which EPR pairs, the entangled states, can be used as quantum channels. In this paper, we present two simple schemes for teleporting a product state of two arbitrary single-particle and an arbitrary two-particle pure entangled state respectively. Alice and Bob have shared an entangle state. Two Bell states are used as quantum channels. Then after Alice measuring her qubits and informing Bob her measurement results, Bob can perfectly reconstruct the original state by performing corresponding unitary operators on his qubits. It shown that a product state of two arbitrary single-particle and an arbitrary two-particle pure entangled state can be teleported perfectly, i.e. the success probabilities of our schemes are both 1. 相似文献
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Ye-Qi Zhang 《Journal of Modern Optics》2013,60(7):593-598
We investigate the entanglement swapping of non-Gaussian states, including squeezed number states, two-mode photon-added states, and two-mode photon-subtracted squeezed states and analyze the entanglement of the swapped states by adopting logarithmic negativity as the measure of entanglement. Furthermore, we examine the fidelity of teleportation protocols for different input states where the swapped states serve as the quantum channel. All these results are compared with that obtained in the case of Gaussian two-mode squeezed vacuum. 相似文献
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By introducing a four-mode unitary operator U = exp[?iλ(X 1 P 2 + X 2 P 3 + X 3 P 4 + X 4 P 1)], we show how a four-mode coherent entangled state can be generated by entangling a two bipartite coherent entangled state. The corresponding squeezed vacuum state U|0000? in four-mode Fock space is derived by virtue of the technique of integration within ordered production of operators, which exhibits the standard squeezing for the four-mode quadratures. A new ideal quantum mechanical representation |α, β, γ? is constructed from U|0000? in the limit of infinite squeezing, which possesses the properties of both coherent and entangled states. The entanglement involved in |α, β, γ? is explained. A scheme for generating |α, β, γ? is presented. 相似文献
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We have demonstrated that micron-size silica beads can be arranged in desired synthetic structure using an optical tweezer in a saline buffered solution. In 3.1 µm silica and water solution we added the right proportion of antistick glycol and NaCl to form a solution in which silica beads brought close to one another can bind by an adhesive electrostatic force without drifting away due to their thermal energy. Then by trapping and dragging one bead at a time using an optical tweezer, we have arranged the silica beads in two-dimensional structures. 相似文献
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Y.S. Weinstein 《Journal of Modern Optics》2013,60(14):1285-1291
The ability to construct large photonic cluster states capable of supporting universal quantum computation relies on fusing together cluster primitives. These fusion operations are probabilistic and the efficiency of the construction process relies on recycling remains of cluster primitives that have undergone failed fusion attempts. Here I consider the effects of the inevitable decoherence that must arise while storing cluster primitives. First, I explore the case where dephased two-qubit cluster states are the basic resource for the construction of all larger cluster states, all fusion operations are successful, and no further dephasing occurs during the construction process. This allows us to explore how decoherence of the most basic, primitive clusters translates into imperfections of the larger cluster states constructed from them. I then assume that decoherence occurs before every attempted fusion operation and determine the best way to build a five-qubit cluster. This requires including the effects of the fusion operation failures. Fidelity is used as the measure of accuracy for the constructed cluster states. Finally, I include a short discussion of photon loss and how it affects the construction of simple photonic clusters. 相似文献
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The first experimental preparation is reported of an ultra-broadband continuously-tunable highly polarization-entangled photon-pair source via spontaneous parametric down-conversion in a single type-II phase-matched bulk periodically-poled KTiOPO4 (PPKTP) crystal. A tuning band of more than 60?nm for the down-converted photons is achieved experimentally, which covers the C+L telecom bands. The photon pair generation rate is about 1.63 × 104 (s mW?nm)?1. The calculated S parameter values of CHSH inequality between 2.60?±?0.04 (minimum) and 2.72?±?0.07 (maximum) over the whole tunable range clearly demonstrate high entanglement of the source. In combination with the dense wavelength-division multiplexing (DWDM) technique, our source could be used to enhance the transmission capacity of a communication channel in the field of quantum communication. 相似文献
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We investigate coupled two-cavity optomechanical systems to show their potential usages by revealing the physical processes. Under two conditions, we deduce the correspondingly effective Hamiltonian with beam splitter type and nondegenerate parametric-down conversion type, respectively. Including the whole interactions, we show that the state transfer and the stationary entanglement between the two mechanical resonators can be achieved. 相似文献
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We apply the Wigner formalism of quantum optics in the Heisenberg picture to study the role of the zeropoint field fluctuations in entanglement swapping produced via parametric down conversion. It is shown that the generation of mode entanglement between two initially non-interacting photons is related to the quadruple correlation properties of the electromagnetic field, through the stochastic properties of the vacuum. The relationship between the process of transferring entanglement and the different zeropoint inputs at the non-linear crystal and the Bell-state analyser is emphasized. 相似文献
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Hong-Yi Fan 《Journal of Modern Optics》2013,60(1):45-51
In many applications of phase-shifting interferometry (PSI) the actually recorded object wave is the diffraction field of an object surface. In this case not only the phase error but also the amplitude error in the retrieval process have effects on the object wave reconstruction in its original plane. In this paper, for the first time that we know, the amplitude errors in wave reconstruction in PSI are discussed systematically. Some general relations between the amplitude errors and the phase errors for three commonly encountered error sources, namely the phase shift error, the light source intensity fluctuation and the detector nonlinearity, are revealed. The analytical expressions of the amplitude and phase errors for six frequently used algorithms in PSI are derived. The statistical variances of the two kinds of error are introduced to describe the overall performance of these algorithms and are quantitatively calculated. A series of computer simulations are also given as a verification of our analyses. These results can be used for evaluating the complete wave errors in PSI and developing new methods for their correction. 相似文献
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Hong-Yi Fan 《Journal of Modern Optics》2013,60(17):1819-1823
Based on the correspondence between the Collins diffraction formula (optical Fresnel transform) and the transform matrix element of a three-parameter two-mode squeezing operator in the entangled state representation 1 we further explore the relationship between output field intensity determined by the Collins formula and the input field's probability distribution along an infinitely thin phase space strip, both in the spatial domain and the frequency domain. The entangled Wigner function is introduced for recapitulating the result. 相似文献
