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Private comparison is the basis of many encryption technologies, and several related Quantum Private Comparison (QPC) protocols have been published in recent years. In these existing protocols, secret information is encoded by using conjugate coding or orthogonal states, and all users are quantum participants. In this paper, a novel semi-quantum private comparison scheme is proposed, which employs Bell entangled states as quantum resources. Two semi-quantum participants compare the equivalence of their private information with the help of a semi-honest third party (TP). Compared with the previous classical protocols, these two semi-quantum users can only make some particular action, such as to measure, prepare and reflect quantum qubits only in the classical basis
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With the emergence of classical communication security problems, quantum communication has been studied more extensively. In this paper, a novel probabilistic hierarchical quantum information splitting protocol is designed by using a non-maximally entangled four-qubit cluster state. Firstly, the sender Alice splits and teleports an arbitrary one-qubit secret state invisibly to three remote agents Bob, Charlie, and David. One agent David is in high grade, the other two agents Bob and Charlie are in low grade. Secondly, the receiver in high grade needs the assistance of one agent in low grade, while the receiver in low grade needs the aid of all agents. While introducing an ancillary qubit, the receiver’s state can be inferred from the POVM measurement result of the ancillary qubit. Finally, with the help of other agents, the receiver can recover the secret state probabilistically by performing certain unitary operation on his own qubit. In addition, the security of the protocol under eavesdropping attacks is analyzed. In this proposed protocol, the agents need only single-qubit measurements to achieve probabilistic hierarchical quantum information splitting, which has appealing advantages in actual experiments. Such a probabilistic hierarchical quantum information splitting protocol hierarchical is expected to be more practical in multipartite quantum cryptography. 相似文献
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Jinqiao Dai Shibin Zhang Yan Chang Xueyang Li Tao Zheng Jinyue Xia 《计算机、材料和连续体（英文）》2020,64(2):1247-1260
In order to enable two parties to exchange their secret information equally, we propose a controlled quantum dialogue protocol based on quantum walks, which implements the equal exchange of secret information between the two parties with the help of the controller TP. The secret information is transmitted via quantum walks, by using this method, the previously required entangled particles do not need to be prepared in the initial phase, and the entangled particles can be produced spontaneously via quantum walks. Furthermore, to resist TP’s dishonest behavior, we use a hash function to verify the correctness of the secret information. The protocol analysis shows that it is safe and reliable facing some attacks, including intercept-measure-resend attack, entanglement attack, dishonest controller’s attack and participant attack. And has a slightly increasing efficiency comparing with the previous protocols. Note that the proposed protocol may be feasible because quantum walks prove to be implemented in different physical systems and experiments. 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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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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In this paper, we first re-examine the previous protocol of controlled quantum secure direct communication of Zhang et al.’s scheme, which was found insecure under two kinds of attacks, fake entangled particles attack and disentanglement attack. Then, by changing the party of the preparation of cluster states and using unitary operations, we present an improved protocol which can avoid these two kinds of attacks. Moreover, the protocol is proposed using the three-qubit partially entangled set of states. It is more efficient by only using three particles rather than four or even more to transmit one bit secret information. Given our using state is much easier to prepare for multiqubit states and our protocol needs less measurement resource, it makes this protocol more convenient from an applied point of view. 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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We study numerically the interaction of the Shockley surface state at the Γ-point of Cu(1 1 1) with periodic arrangements of adsorbed/absorbed Cu and Fe atoms. We use an spd tight-binding hamiltonian with the local basis enlarged to account for electron spillover. 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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We propose a comprehensive experimental scheme to generate and teleport GHZ states of any number of photons as well as to accomplish the process of open-destination teleportation of a single photon's arbitrary state. The equipment and techniques which are used in our scheme are all feasible under current technology. Moreover, we make a direct extension of the above cases and investigate the open-destination teleportation of any M-photon general GHZ states with a brief diagram. 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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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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By employing the tensor analysis technique, we propose three schemes of controlled teleportation: series controlled, circular controlled and network controlled teleportation. We discuss the necessary and sufficient condition for realizing these schemes, in which we use a general two-qubit entangled state instead of the GHZ state as the communication channel. This enables successful implementation of teleportation without using the Hadamard operation. 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