量子网络中有三个节点,每个节点有一对全同量子比特,这六个量子比特最初处于一种量子纠缠纯态[Chen et al.Phys Rev A,2006,74:032324].本文考虑三个节点中的量子比特都发生了混淆,利用混淆后的量子态作为量子通道,提出了一个三方量子...量子网络中有三个节点,每个节点有一对全同量子比特,这六个量子比特最初处于一种量子纠缠纯态[Chen et al.Phys Rev A,2006,74:032324].本文考虑三个节点中的量子比特都发生了混淆,利用混淆后的量子态作为量子通道,提出了一个三方量子态分享协议.文中分析讨论了该协议的安全性、成功概率、分享者对称性和它们的深层物理以及协议的实验可行性.研究发现,该协议是安全的;任一分享者都可以1/2概率获取被分享量子态;根据当前实验技术协议切实可行.展开更多
In this paper, we study quantum teleportation of atomic states via a hybrid entangled state （HES） involving an atom and a cavity field. And we investigate how to implement controlled phase （CP） gates between atomi...In this paper, we study quantum teleportation of atomic states via a hybrid entangled state （HES） involving an atom and a cavity field. And we investigate how to implement controlled phase （CP） gates between atomic internal states and coherent states of cavity field. We also discuss the methods of distinguishing coherent states [±α〉 in a cavity. Finally, a brief discussion about the feasibility of this scheme in experiment is presented.展开更多
In this paper,we study quadrature squeezings of two Bose-Einstein condensates with collision and non- classical properties of pair entanglement in four wave mixing in Bose-Einstein condensates.With the aid of a numeri...In this paper,we study quadrature squeezings of two Bose-Einstein condensates with collision and non- classical properties of pair entanglement in four wave mixing in Bose-Einstein condensates.With the aid of a numerical method,we find that the two modes(pair entanglement modes)α_1 and α_2 may exhibit quadrature squeezing,in which they are affected by the initial phase.It is shown that the two pump modes exhibit the same super-Poissonian distri- bution.The analysis for the mode-mode correlation shows that there always exists a violation of the Cauchy-Schwartz inequality,which means that correlation between the two pump modes is nonclassical.展开更多
An analytical method based on four-wave mixing （FWM） is here developed to study the generation of entangled state in an asymmetric semiconductor double quantum well structure. It is found that the maximally entangle...An analytical method based on four-wave mixing （FWM） is here developed to study the generation of entangled state in an asymmetric semiconductor double quantum well structure. It is found that the maximally entangled state of two beams （the probe and four-wave mixing beams） can be achieved in an appropriate condition. Moreover, we also show that the two entangled beams propagate with ultraslow group velocity in the semiconductor medium. This investigation can be used for achieving the entangled beams in the semiconductor solid-state medium, which is much more practical than that in an atomic medium because of its flexible design and the wide adjustable parameters.展开更多
We propose a novel quantum key distribution scheme by using the SAM-OAM hybrid entangled state as the physical resource.To obtain this state,the polarization entangled photon pairs are created by the spontaneous param...We propose a novel quantum key distribution scheme by using the SAM-OAM hybrid entangled state as the physical resource.To obtain this state,the polarization entangled photon pairs are created by the spontaneous parametric down conversion process,and then,the q-plate acts as a SAM-to-OAM transverter to transform the polarization entangled pairs into the hybrid entangled pattern,which opens the possibility to exploit the features of the higher-dimensional space of OAM state to encode information.In the manipulation and encoding process,Alice performs the SAM measurement by modulating the polarization stateπ lθx on one photon,whereas Bob modulates the OAM sector state lx' on the other photon to encode his key elements using the designed holograms which is implemented by the computer-controlled SLM.With coincidence measurement,Alice could extract the key information.It is showed that N-based keys can be encoded with each pair of entangled photon,and this scheme is robust against Eve’s individual attack.Also,the MUBs are not used.Alice and Bob do not need the classical communication for the key recovery.展开更多
文摘量子网络中有三个节点,每个节点有一对全同量子比特,这六个量子比特最初处于一种量子纠缠纯态[Chen et al.Phys Rev A,2006,74:032324].本文考虑三个节点中的量子比特都发生了混淆,利用混淆后的量子态作为量子通道,提出了一个三方量子态分享协议.文中分析讨论了该协议的安全性、成功概率、分享者对称性和它们的深层物理以及协议的实验可行性.研究发现,该协议是安全的;任一分享者都可以1/2概率获取被分享量子态;根据当前实验技术协议切实可行.
基金The project supported by the Scientific Research Fund of Education Department of Hunan Province under Grant No.06C354 and the Natural Science Foundation of Hunan Province under Grant No. 06JJ5015 tCorresponding author,
文摘In this paper, we study quantum teleportation of atomic states via a hybrid entangled state （HES） involving an atom and a cavity field. And we investigate how to implement controlled phase （CP） gates between atomic internal states and coherent states of cavity field. We also discuss the methods of distinguishing coherent states [±α〉 in a cavity. Finally, a brief discussion about the feasibility of this scheme in experiment is presented.
文摘In this paper,we study quadrature squeezings of two Bose-Einstein condensates with collision and non- classical properties of pair entanglement in four wave mixing in Bose-Einstein condensates.With the aid of a numerical method,we find that the two modes(pair entanglement modes)α_1 and α_2 may exhibit quadrature squeezing,in which they are affected by the initial phase.It is shown that the two pump modes exhibit the same super-Poissonian distri- bution.The analysis for the mode-mode correlation shows that there always exists a violation of the Cauchy-Schwartz inequality,which means that correlation between the two pump modes is nonclassical.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10575040, 10874050, and 10904033by the National Basic Research Program of China under Grant No. 2005CB724508by the Programme for Talent Introduction of Hubei Normal University under Grant No. 2008F10
文摘An analytical method based on four-wave mixing （FWM） is here developed to study the generation of entangled state in an asymmetric semiconductor double quantum well structure. It is found that the maximally entangled state of two beams （the probe and four-wave mixing beams） can be achieved in an appropriate condition. Moreover, we also show that the two entangled beams propagate with ultraslow group velocity in the semiconductor medium. This investigation can be used for achieving the entangled beams in the semiconductor solid-state medium, which is much more practical than that in an atomic medium because of its flexible design and the wide adjustable parameters.
基金supported by the National Cryptography Development Foundation of China(Grant No.MMJJ201401011)the Science and Technology Program of Guangzhou,China(Grant Nos.2013J4500095 and 2014J4100050)
文摘We propose a novel quantum key distribution scheme by using the SAM-OAM hybrid entangled state as the physical resource.To obtain this state,the polarization entangled photon pairs are created by the spontaneous parametric down conversion process,and then,the q-plate acts as a SAM-to-OAM transverter to transform the polarization entangled pairs into the hybrid entangled pattern,which opens the possibility to exploit the features of the higher-dimensional space of OAM state to encode information.In the manipulation and encoding process,Alice performs the SAM measurement by modulating the polarization stateπ lθx on one photon,whereas Bob modulates the OAM sector state lx' on the other photon to encode his key elements using the designed holograms which is implemented by the computer-controlled SLM.With coincidence measurement,Alice could extract the key information.It is showed that N-based keys can be encoded with each pair of entangled photon,and this scheme is robust against Eve’s individual attack.Also,the MUBs are not used.Alice and Bob do not need the classical communication for the key recovery.
