Theoretical Study On Reference-Frame-Independent Quantum Key Distribution

With the increasing computing power of modern computers,the traditional communication encryption technology will face huge challenges.Moreover,the development of research on quantum computers will further increase people’s worries.However,the emergence of quantum communication technology can just solve this problem.Quantum key distribution is the most mature and practical application of quantum physics in informatics,and it is also the most widely used technology in quantum communication technology.The security of traditional communication cryptography is based on the complexity of solving mathematical problems,which in principle can be cracked.While the unconditional security of quantum key distribution can be guaranteed by quantum physics.In practical,the quantum key distribution system which always use phase coding or polarization coding,need to real-time alignment of reference frames of sender and receiver.However reference-frame-independent quantum key distribution protocol can distribute the keys securely while the reference frames of sender and receiver exist a unkown deviation.Own to the property of reference-frame-independent quantum key distribution,in recent years,a lot of research results have been achieved in theoretical and experimental at domestic and international.This article focuses on the reference-frame-independent quantum key distribution protocol.We introduce the research background,research status,and basic knowledge of quantum key distribution.Combined with some related research results at domestic and abroad,the following research points are carried out:1.We study the performance of a reference-frame-independent quantum key distributionprotocol with heralded pair-coherent sources.Traditional weak coherent sources inevitablyexist non-negligible multiphoton and vacuum commponents,while the single photoncommponents in the heralded pair-coherent source is up to 99%,and heralded pair-coherentsource contains significantly lower vacuum component and multiphoton component thanweak coherent sources,so it is a good choice for quantum key distribution systems.Simulation results show that both in terms of secure transmission distance and keygeneration rate,the scheme utilizing heralded pair-coherent sources can greatly exceed theone using weak coherent sources.Meantime,we do comparisons on parameter estimationsbetween applying heralded pair-coherent sources and using weak coherent sources,anddemonstrate that the former shows more accurate than the latter.2.We study the performance of the one-decoy state reference-frame-independent quantum keydistribution protocol.In practical,due to the imperfection of the light source,the quantumkey distribution systems exist potential possibility of attacked.In order to resist potentialphoton-number-splitting attacks in practical quantum key distribution systems,the decoystate method is generally used,which always adopt one signal state and two decoy states.Although the problem of photon-number-splitting attack can be solved well,it also putsforward higher requirements for the actual control circuit.We compare the performance ofreference-frame-independent quantum key distribution protocol with one decoy state andtwo decoy state.Simulation results show that when using one(non-vacuum state)decoystate,the key generation rate and secure transmission of the protocol are comparable to thetwo-decoy state method.However,the use of a single decoy scheme will undoubtedlyreduce the requirements for control circuit.