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Yong-gang Tan

Publications and source records attributed to Yong-gang Tan.

6 recordsLinked to original sources
arXiv2015

Excluding the local hidden variable theory with time-reversal Bell test

A time-reversal Bell test protocol is proposed. The quantum states are prepared by faraway separated partners and transferred to the third partner who carries out Bell basis measurement on them to post-select the Einstein-Podolsky-Rosen (EPR) pairs. If some loopholes open, similar as that in normal Bell test, the Bell violation in the present protocol is apt to be interpreted with local hidden variable (lhv) theory. With some modifications on the protocol, the lhvs at both sides are prevented to exchange their information. Thus they only function locally and cannot affect the behaviors of the states at the other sides. However, Bell violation can still be obtained in this case. It means that Bell violation is realized with the lhv theory excluded. Because high detection efficiency is not compulsory, this protocol can be realized with present technology.

quant-ph↗
arXiv2012

Symmetric Device-Independent Quantum Key Distribution Against General Attack

A symmetric device-independent quantum key distribution (DIQKD) protocol is proposed in this paper, with Holevo limit and subadditivity of von Neumann entropy, one can bound Eve's ability with collective attack. Together with symmetry of this protocol, the state Eve prepared for Alice and Bob, and at the same time, her eavesdropping on Alice's and Bob's measurements can be definitely inferred at the assumption that Eve aims at maximizing her information gain. The optimal state under this circumstance can be solely bounded with Alice and Bob's statistical results on the quantity of Clauser-Horne-Shimony-Holt (CHSH) polynomial $S$, that is, our symmetric DIQKD has the same secure basis as that of Ekert91 protocol.

quant-ph↗
arXiv2012

Fake state attack on practically decoy state quantum key distribution

In this paper, security of practically decoy state quantum key distribution under fake state attack is considered. If quantum key distribution is insecure under this type of attack, decoy sources can not also provide it with enough security. Strictly analysis shows that Eve should eavesdrop with the aid of photon-number-resolving instruments. In practical implementation of decoy state quantum key distribution where statistical fluctuation is considered, however, Eve can attack it successfully with threshold detectors.

quant-ph↗
arXiv2008

Classical Correlation in Quantum Dialogue

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.

quant-ph↗
arXiv2005

Photon-number-solving Decoy State Quantum Key Distribution

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

quant-ph↗