The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD h...The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD has become a focus recently. To improve the practieM performance of the two-way QKD, we present a security analysis of a two-way QKD protocol based on the decoy method with heralded single-photon sources （HSPSs）. We make use of two approaches to calculate the yield and the quantum bit error rate of single-photon and two-photon pulses. Then we present the secret key generation rate based on the GLLP formula. The numerical simulation shows that the protocol with HSPSs has an advantage in the secure distance compared with weak coherent state sources. In addition, we present the final secret key by considering the statistical fluctuation of the yield generation rate of the LM05 protocol with finite resources and the error rate.展开更多
Since a critical report on China's medical system reform was issued in mid-2005, it has become a major bone of contention. In April 2007, the State Council, China's cabinet, decided that from this year,economi...Since a critical report on China's medical system reform was issued in mid-2005, it has become a major bone of contention. In April 2007, the State Council, China's cabinet, decided that from this year,economically developed provinces should single out one or two cities to experiment with the urban basic medical insurance system that focuses on serious diseases. Meanwhile,the Ministry of Health invited seven research institutions to independently work out medical reform schemes. Ministry sources said that the finalized scheme would come into effect later this year.But will these efforts help to ease the problem of high medical expenses in China? And is it true that current problems of China's medical system lie in the "over marketization" as some experts have pointed out? Professor Cai Jiangnan, from the School of Economics, Fudan University,and Professor Zhou Qiren,from the China Center for Economic Research, Peking University,put forward their different views on this issue, based on their long-term research of China 's medical system reform.展开更多
基金Supported by the National Basic Research Program of China under Grant No 2013CB338002the National Natural Science Foundation of China under Grant Nos 11304397 and 61505261
文摘The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD has become a focus recently. To improve the practieM performance of the two-way QKD, we present a security analysis of a two-way QKD protocol based on the decoy method with heralded single-photon sources （HSPSs）. We make use of two approaches to calculate the yield and the quantum bit error rate of single-photon and two-photon pulses. Then we present the secret key generation rate based on the GLLP formula. The numerical simulation shows that the protocol with HSPSs has an advantage in the secure distance compared with weak coherent state sources. In addition, we present the final secret key by considering the statistical fluctuation of the yield generation rate of the LM05 protocol with finite resources and the error rate.
文摘Since a critical report on China's medical system reform was issued in mid-2005, it has become a major bone of contention. In April 2007, the State Council, China's cabinet, decided that from this year,economically developed provinces should single out one or two cities to experiment with the urban basic medical insurance system that focuses on serious diseases. Meanwhile,the Ministry of Health invited seven research institutions to independently work out medical reform schemes. Ministry sources said that the finalized scheme would come into effect later this year.But will these efforts help to ease the problem of high medical expenses in China? And is it true that current problems of China's medical system lie in the "over marketization" as some experts have pointed out? Professor Cai Jiangnan, from the School of Economics, Fudan University,and Professor Zhou Qiren,from the China Center for Economic Research, Peking University,put forward their different views on this issue, based on their long-term research of China 's medical system reform.
