共查询到20条相似文献,搜索用时 62 毫秒
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We present a controlled teleportation scheme for teleporting an arbitrary superposition state of an M-qudit quantum system. The scheme employs only one entangled state as quantum channel, which consists of the qudits from Alice, Bob and every agent. The quantum operations used in the teleportation process are a series of qudit Bell measurements, single-qudit projective measurements, qudit H-gates, qudit-Pauli gates and qudit phase gates. It is shown that the original state can be restored by the receiver only on the condition that all the agents collaborate. If any agent does not cooperate, the original state can not be fully recovered. 相似文献
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We study quantum games in which the players have different strategic spaces. We find that the player who can use a quantum strategic space does not always possess more payoffs than the player who is restricted to apply only classical strategies. We find the condition of the classical player getting more payoffs than the quantum player. We also find that the game exhibits intriguing structures. 相似文献
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A New Quantum Secure Direct Communication Protocol Using Decoherence-Free Subspace 总被引:1,自引:0,他引:1 下载免费PDF全文
A new quantum secure direct communication (QSDC) protocol is proposed by using decoherence free subspace (DFS) to avoid insecurity of the present QSDC protocols in a quantum noise channel. This protocol makes it easily for Bob and Alice to find eavesdropping in channel because the collective dephasing noise disappears in DFS. The probability of successful attack by Eve in this protocol is smaller than in BB84 protocol. Thus this protocol realizes secure QSDC and is feasible with present-day technology. 相似文献
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Coherent tunnelling is studied in the framework of the effective mass approximation for an asymmetric coupled quantum well. The Hartree potential due to the electron-electron interaction is considered in our calculation. The effects of the longitudinal and transverse magnetic field on coherent tunnelling characteristics are discussed. It has been found that the external field plays an important role in modulating the electron states. 相似文献
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A two-step quantum secure direct dialogue protocol using Einstein-Podolsky-Rosen(EPR)pair block is proposed.In the protocol,the dialogue messages are encoded on series of qubits and sent through a quantum channel directly.The security of the protocol is assured by its connection to the two-step quantum secure direct communication protocol,which has been proved secure.This protocol has several advantages.It is a direct communication protocol that does not require a separate classical communication for the ciphertext.It has high capacity as two bits of secret messages can be transmitted by an EPR pair.As a dialogue protocol,the two parties can speak to each other either simultaneously or sequentially. 相似文献
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We present a mixed entanglement distillation protocol by means of the parity measurement of qubits. Without the use of controlled-NOT (CNOT) operations, the efficiency of our protocol can approach that of the CNOT protocol. In comparison, the total successful probability of our protocol can reach a quantity twice as large as that of the linear optics-based protocol. 相似文献
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We consider the use of qutrits in a two way deterministic quantum cryptographic protocol which exhibits a higher level of security. We analyse the security of the protocol in the context of the Intercept Resend Strategy. The protocol which transmits a qutrit is naturally limited to not utilising all the available maximally overlapping basis due to a no go theorem not unlike the universal-NOT. We further propose another protocol to generalise the protocol above against the no-go theorem. 相似文献
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We prove that the 1984 protocol of Bennett and Brassard (BB84) for quantum key distribution is secure. We first give a key distribution protocol based on entanglement purification, which can be proven secure using methods from Lo and Chau's proof of security for a similar protocol. We then show that the security of this protocol implies the security of BB84. The entanglement purification based protocol uses Calderbank-Shor-Steane codes, and properties of these codes are used to remove the use of quantum computation from the Lo-Chau protocol. 相似文献
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水声通信网络是水声研究的一个热点问题。由于水下声网络带宽窄、传播延迟大、能量受限等特点,无线电网络中一些成熟的路由协议,如DSDV、AODV等的应用受到了很大的限制。本文结合按需距离矢量(AODV)路由协议和地理位置协议,提出了一种适用于水下网络的路由协议——定向搜索AODV(DSAODV)路由协议。DSAODV协议利用地理位置信息约束路由请求分组(RREQ)寻找路由的范围,降低了路由寻径的开销,减少了网络拥塞。仿真结果表明,DSAODV协议在吞吐量、协议开销等方面都优于AODV协议。 相似文献
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This paper presents a simple way for an eavesdropper to eavesdrop freely the secret message in the experimental realization of quantum communication protocol proposed by Beige et al (2002 Acta Phys. Pol. A 101 357). Moreover, it introduces an efficient quantum secure communication protocol based on a publicly known key with decoy photons and two biased bases by modifying the original protocol. The total efficiency of this new protocol is double that of the original one. With a low noise quantum channel, this protocol can be used for transmitting a secret message. At present, this protocol is good for generating a private key efficiently, 相似文献
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To solve the problems of updating sub-secrets or secrets as well as adding or deleting agents in the quantum secret sharing protocol, we propose a two-particle transform of Bell states, and consequently present a novel dynamic quantum secret sharing protocol. The new protocol can not only resist some typical attacks, but also be more efficient than the existing protocols. Furthermore, we take advantage of the protocol to establish the dynamic secret sharing of a quantum state protocol for two-particle maximum entangled states. 相似文献
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In this paper, a protocol for quantum millionaire problem with continuous variables is proposed. In the protocol, two participants can compare the values of their fortune with the assistance of a semi-trusted third party (STTP). Only EPR states are exploited in our protocol while most other protocols exploited d-dimensional Bell states. Two participants are just required to perform single particle operations, which makes our protocol more efficiently. Our protocol can ensure fairness, correctness, security and high efficiency as well. In our protocol, only the two participants can deduce the results of comparisons, others include STTP will learn no information. Our protocol can resist various kinds of attacks from both the outside eavesdroppers and the inside participants, even the STTP. 相似文献
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We propose a three-party quantum secure direct communication(QSDC) protocol with hyperentanglement in both spatial-mode and polarization degrees of freedom. The secret message can be encoded independently with desired unitary operations in two degrees of freedom. In this protocol, a party can synchronously obtain the other two parties' messages. Compared with previous three-party QSDC protocols, our protocol has several advantages. First, the single photons in our protocol are only required to transmit for three times. This advantage makes this protocol simple and useful. Second, Alice and Bob can send different secret messages to Charlie, respectively. Finally, with hyperentanglement, this protocol has a higher information capacity than other protocols. 相似文献