Quantum state regeneration in entanglement based quantum key distribution protocols

2014 ◽  
Author(s):  
Reinhard Erdmann
Keyword(s):  
Quantum State ◽  
Quantum Key Distribution ◽  
Key Distribution

scholarly journals SECURE QUANTUM CARRIERS FOR QUANTUM STATE SHARING

2012 ◽  
Vol 10 (02) ◽  
pp. 1250018 ◽  
Author(s):  
VAHID KARIMIPOUR ◽  
MILAD MARVIAN
Keyword(s):  
Quantum State ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Quantum State Sharing ◽  
External Agents ◽  
In Transit ◽  
Continuous Running ◽  
Threshold Schemes

We develop the concept of quantum carrier and show that messages can be uploaded and downloaded from this carrier and while in transit, these messages are hidden from external agents. We explain in detail the working of the quantum carrier for different communication tasks, including quantum key distribution, classical secret and quantum state sharing among a set of n players according to general threshold schemes. The security of the protocol is discussed and it is shown that only the legitimate subsets can retrieve the secret messages, the collaboration of all the parties is needed for the continuous running of the protocol and maintaining the carrier.

scholarly journals Twin-Field Quantum Key Distribution over 511 km Optical Fiber Linking two Distant Metropolitans

2021 ◽  
Author(s):  
Jiu-Peng Chen ◽  
Chi Zhang ◽  
Yang Liu ◽  
Cong Jiang ◽  
Weijun Zhang ◽  
...  
Keyword(s):  
Quantum State ◽  
Quantum Key Distribution ◽  
Large Scale ◽  
Single Photon ◽  
Key Distribution ◽  
Test System ◽  
Long Distance ◽  
Quantum Networks ◽  
The Cost ◽  
Remarkable Progress

Abstract The basic principle of quantum mechanics guarantee the unconditional security of quantum key distribution (QKD) at the cost of inability of amplification of quantum state. As a result, despite remarkable progress in worldwide metropolitan QKD networks over the past decades, long haul fiber QKD network without trustful relay has not been achieved yet. Here, through sending-or-not-sending (SNS) protocol, we complete a twin field QKD (TF-QKD) and distribute secure keys without any trusted repeater over a 511 km long haul fiber trunk linking two distant metropolitans. Our secure key rate is around 3 orders of magnitudes greater than what is expected if the previous QKD field test system over the same length were applied. The efficient quantum-state transmission and stable single-photon interference over such a long distance deployed fiber paves the way to large-scale fiber quantum networks.

Finite-key analysis for quantum key distribution with decoy states

2011 ◽  
Vol 11 (5&6) ◽  
pp. 374-399
Author(s):  
Ting-Ting Song ◽  
Jie Zhang ◽  
Su-Juan Qin ◽  
Fei Gao ◽  
Qiao-Yan Wen
Keyword(s):  
Quantum State ◽  
Error Rate ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Finite Resource ◽  
Photon Pulse ◽  
Security Bound

We analyze the security of finite-resource quantum key distribution with decoy states, and present the security bound for the practical implementations by introducing the deviations of the probability of sending a $k$-photon pulse and the error rate of the quantum state. The bound is simulated under reasonable values of the observed parameters. Compared with the previous works, the security bound is more stringent.

scholarly journals Understanding of Various Type of Unambiguous Discrimination in View of Coherence Distribution

Entropy ◽  
2020 ◽  
Vol 22 (12) ◽  
pp. 1422
Author(s):  
Min Namkung ◽  
Younghun Kwon
Keyword(s):  
Quantum Information ◽  
Quantum State ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Quantum States ◽  
Quantum State Discrimination ◽  
Mixed States ◽  
Generalized Measurement ◽  
Unambiguous Discrimination ◽  
State Discrimination

Unambiguous quantum state discrimination is a strategy where the conclusive result can always be trusted. This strategy is very important, since it can be used for various quantum information protocols, including quantum key distribution. However, in the view of quantumness, it is not clear what is going on in performing unambiguous quantum state discrimination. To answer the question, we investigate coherence distribution when unambiguous discrimination is performed by generalized measurement. Specially, we study coherence distribution in three cases, which consist of unambiguous quantum state discrimination, sequential quantum state discrimination, and assisted optimal discrimination, which are considered to be a family of unambiguous quantum state discrimination. In this investigation, we show that the structure of generalized measurements performing various types of unambiguous quantum state discrimination can be understood in terms of coherence distribution. Our result is not limited to the discrimination of two pure quantum states, but it is extended to the discrimination of two mixed states.

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