Yong-gang Tan

Wuhan Institute of Physics and Mathematics, Wu-han-shih, Hubei, China

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Publications (5)12.84 Total impact

  • Yong-gang Tan, Hua Lu, Qing-yu Cai
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    ABSTRACT: A Comment on the Letter by Michel Boyer, Dan Kenigsberg, and Tal Mor, [Phys. Rev. Lett. 99, 140501 (2007)10.1103/PhysRevLett.99.140501]. The authors of the Letter offer a Reply.
    Physical Review Letters 04/2009; 102(9):098901; author reply 098902. · 7.73 Impact Factor
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    Yong-gang Tan, Qing-yu Cai
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    ABSTRACT: Classical communications are used in the post-processing procedure of quantum key distribution. Since the security of quantum key distribution is based on the principles of quantum mechanics, intuitively the secret key can only be derived from the quantum states. We find that classical communications are incorrectly used in the so-called quantum dialogue type protocols. In these protocols, public communications are used to transmit secret messages. Our calculations show that half of Alice's and Bob's secret message is leaked through classical channel. By applying Holevo bound, we can see that the quantum efficiency claimed in the quantum dialogue type of protocols is not achievable.
    International Journal of Quantum Information 03/2008; · 0.92 Impact Factor
  • Yong-Gang Tan, Qing-Yu Cai, Ting-Yun Shi
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    ABSTRACT: This paper proves that it is impossible to identify orthogonally time-separated Bell states. If two qubits of A Bell state interact with the measurement apparatus at different time, any attempt to identify this state will disturb it.
    Chinese Physics B 01/2008; 17(9):3194-3197. · 1.15 Impact Factor
  • Qing-yu Cai, Yong-gang Tan
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    ABSTRACT: In this paper, a photon-number-resolving decoy-state quantum key distribution (QKD) scheme is presented based on recent experimental advancements. A new upper bound on the fraction of counts caused by multiphoton pulses is given, which seems inherent as long as weak coherent sources and high lossy channel are used. This implies that our scheme is optimal in long-distance QKD with weak coherent sources. We show that Eve’s coherent multiphoton pulse (CMP) attack is more efficient than a symmetric individual attack when the quantum bit error rate is small, so that the CMP attack should be considered to ensure the security of the final key. Our results show that a not-so-weak pulse can be used to transmit the key. Optimal intensity of the laser source is presented which provides a 23.9 km increase in the transmission distance.
    Physical Review A 03/2006; 73(3). · 3.04 Impact Factor
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    Qing-yu Cai, Yong-gang Tan
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    ABSTRACT: In this paper, a photon-number-resolving decoy state quantum key distribution scheme is presented based on recent experimental advancements. A new upper bound on the fraction of counts caused by multiphoton pulses is given. This upper bound is independent of intensity of the decoy source, so that both the signal pulses and the decoy pulses can be used to generate the raw key after verified the security of the communication. This upper bound is also the lower bound on the fraction of counts caused by multiphoton pulses as long as faint coherent sources and high lossy channels are used. We show that Eve's coherent multiphoton pulse (CMP) attack is more efficient than symmetric individual (SI) attack when quantum bit error rate is small, so that CMP attack should be considered to ensure the security of the final key. finally, optimal intensity of laser source is presented which provides 23.9 km increase in the transmission distance. 03.67.Dd
    09/2005;