We propose an efficient scheme for realizing quantum dense coding with three-particle GHZ state in separated low-Q cavities. In this paper, the GHZ state is first prepared with three atoms trapped, respectively, in th...We propose an efficient scheme for realizing quantum dense coding with three-particle GHZ state in separated low-Q cavities. In this paper, the GHZ state is first prepared with three atoms trapped, respectively, in three spatial separated cavities. Meanwhile, with the assistance of a coherent optical pulse and X-quadrature homodyne measurement, we can im- plement quantum dense coding with three-particle GHZ state with a higher probability. Our scheme can also be generalized to realize N-particle quantum dense coding.展开更多
Following a recent proposal （Phys. Left. A 346 （2005） 330） about quantum dense coding using a tripartite entangled GHZ state and W state, this paper proposes an experimentally feasible scheme for dense coding in c...Following a recent proposal （Phys. Left. A 346 （2005） 330） about quantum dense coding using a tripartite entangled GHZ state and W state, this paper proposes an experimentally feasible scheme for dense coding in cavity QED by using another peculiar tripartite entangled state. In the scheme the atoms interact simultaneously with a highly detuned cavity mode with the assistance of a classical field, the successful probability of dense coding scheme with this peculiar tripartite entangled state equals 1.展开更多
An experimentally feasible protocol for realizing dense coding by using a class of W-state in cavity quantum electrodynamics （QED） is proposed in this paper. The prominent advantage of our scheme is that the success...An experimentally feasible protocol for realizing dense coding by using a class of W-state in cavity quantum electrodynamics （QED） is proposed in this paper. The prominent advantage of our scheme is that the successful probability of the dense coding with a W-class state can reach 1. In addition, the scheme can be implemented by the present cavity QED techniques.展开更多
In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no ...In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no longer limited to only one quantum state. We encode a single quantum state into a five-particle entangled state before being transferred to the sender. We designed an automatic error-correction circuit to correct errors caused by noise. We also simplify the design process for a multiple quantum error-correction circuit. We compare error-correction schemes for five and three entangled particles in terms of efficiency and capabilities. The results show that error-correction efficiency and fidelity are im- proved.展开更多
This paper proposes an experimentally feasible scheme for implementing quantum dense coding of trapped-ion system in decoherence-free states. As the phase changes due to time evolution of components with different eig...This paper proposes an experimentally feasible scheme for implementing quantum dense coding of trapped-ion system in decoherence-free states. As the phase changes due to time evolution of components with different eigenenergies of quantum superposition are completely frozen, quantum dense coding based on this model would be perfect. The scheme is insensitive to heating of vibrational mode and Bell states can be exactly distinguished via detecting the ionic state.展开更多
In this paper, we investigate perfect quantum teleportation and dense coding by using an 2N-qubit W state channel. In the quantum teleportation scheme, an unknown N-qubit entangled state can be perfectly teleported. O...In this paper, we investigate perfect quantum teleportation and dense coding by using an 2N-qubit W state channel. In the quantum teleportation scheme, an unknown N-qubit entangled state can be perfectly teleported. One ebit of entanglement and two bits of classical communication are consumed in the teleportation process, just like when using the Bell state channel. While N ＋ 1 bits of classical information can be transmitted by only sending N particles in the dense coding protocol.展开更多
We investigate schemes for quantum secret sharing and quantum dense coding via tripartite entangled states. We present a scheme for sharing classical information via entanglement swapping using two tripartite entangle...We investigate schemes for quantum secret sharing and quantum dense coding via tripartite entangled states. We present a scheme for sharing classical information via entanglement swapping using two tripartite entangled GHZ states. In order to throw light upon the security affairs of the quantum dense coding protocol, we also suggest a secure quantum dense coding scheme via W state by analogy with the theory of sharing information among involved users.展开更多
The paper introduces the state reduction algorithm and accelerated state reduction algorithm are used to compute the distance weight enumerator(transfer function) T[x,y] of convolutional codes.Next use computer simula...The paper introduces the state reduction algorithm and accelerated state reduction algorithm are used to compute the distance weight enumerator(transfer function) T[x,y] of convolutional codes.Next use computer simulation to compare upper bound on the bit error probability on an additive white Gaussian noise (AWGN) for maximum free distance (MFD) codes of previously found and optimum distance spectrum (ODS) codes with rate 1/4,overall constraint length are 5 and 7,respectively. Finally,a method of how to search for good convolutional codes is given.展开更多
The paper introduces the state reduction algorithm and accelerated state reduction algorithm are used to compute the distance weight enumerator(transfer function)T[x,y] of convolutional codes.Next use computer simulat...The paper introduces the state reduction algorithm and accelerated state reduction algorithm are used to compute the distance weight enumerator(transfer function)T[x,y] of convolutional codes.Next use computer simulation to compare upper bound on the bit error probability on an additive white Gaussian noise(AWGN) for maximum free distance(MFD) codes of previously found and optimum distance spectrum(ODS) codes with rate 1/4,overall constraint length are 5 and 7,respectively.Finally,a method of how to search for good convolutional codes is given.展开更多
Let C be a free cyclic code over Zp^a and dim pC = k. In the paper, we prove that if the k characteristic generators of C are p-linearly independent then the corresponding nα- k characteristic generators of C^⊥ are ...Let C be a free cyclic code over Zp^a and dim pC = k. In the paper, we prove that if the k characteristic generators of C are p-linearly independent then the corresponding nα- k characteristic generators of C^⊥ are p-linearly independent. We then show that to any trellis that can be constructed from k p-linearly independent characteristic generators of C, there exists a trellis for C^⊥ with the same state-complexity profile, which generalizes the conjecture of Koetter and Vardy to a free cyclic code over Zpo.展开更多
Wireless information and powered transfer networks(WIPT) has recently been implemented in 5th generation wireless networks. In this paper, we consider half-duplex relaying system in which the energy constrained relay ...Wireless information and powered transfer networks(WIPT) has recently been implemented in 5th generation wireless networks. In this paper, we consider half-duplex relaying system in which the energy constrained relay node collects energy via radio frequency(RF) signals from the surrounding resources. Regarding energy harvesting protocol, we propose power time switching-based relaying(PTSR) architecture for both amplify-and-forward(AF) and decode-and-forward(DF). Especially, we reveal the analytical expressions of achievable throughput, ergodic capacity and energy-efficient in case of imperfect channel state information(CSI) for both AF and DF network. Through numerical analysis, we analyse the throughput performance, energy-efficient and ergodic capacity for different parameters, including power splitting ratio and energy harvesting time. Moreover, we also depict the performance comparison between AF and DF network with perfect and imperfect CSI. The results in numerical analysis reveal that the result of AF relaying network is less significant than DF relaying network in the various scenarios.展开更多
It is often necessary to recognize human mouth-states for detecting the number of audio sources and improving the speech recognition capability of an intelligent robot auditory system. A human mouth-state recognition ...It is often necessary to recognize human mouth-states for detecting the number of audio sources and improving the speech recognition capability of an intelligent robot auditory system. A human mouth-state recognition method based on image warping and sparse representation( SR) combined with homotopy is proposed.Using properly warped training mouth-state images as atoms of the overcomplete dictionary overcomes the impact of the diversity of the mouths' scales,shapes and positions so that further improvement of the robustness can be achieved and the requirement for a large number of training samples can be relieved. The homotopy method is employed to compute the expansion coefficients effectively,i. e.,for sparse coding. The orthogonal matching pursuit( OMP) is also tested and compared with the homototy method. Experimental results and comparisons with the state-of-the-art methods have proved the effectiveness of the proposed approach.展开更多
Physical-layer network coding （PNC） has the potential to significantly improve the throughput of wireless networks where the channels can be modeled as additive white Gaussian noise （AWGN） channel. As extending to...Physical-layer network coding （PNC） has the potential to significantly improve the throughput of wireless networks where the channels can be modeled as additive white Gaussian noise （AWGN） channel. As extending to mul- tiple channels, this technique requires both amplitude and phase compensation at each transmitter and will lead to inef- ficient systems yielding no diversity even with perfect channel state information （CSI）. In order to avoid these limita- tions, we apply network coding with diversity （NCD） to achieve a form of selection diversity and extend NCD to coop- erative multiple access channels in this paper. However, in practical wireless communication systems, the CSI could become outdated due to the difference between the CSI used in the relay selection and data transmission phases. Hence, the selected relay may not be the best one during data transmission phase due to the dynamic change in the wireless channels. Therefore, we first explore the relation between the present and past CSIs. Exploiting this relationship, the NCD scheme with outdated CSI is investigated based on the past CSI. To evaluate the performance of this scheme, an information-theoretic metric, namely the outage capacity, is studied under this condition.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11074002 and 61275119)the Doctoral Foundation of the Ministry of Education of China(Grant No.20103401110003)the Natural Science Research Project of Education Department of Anhui Province,China(Grant Nos.KJ2013A205,KJ2011ZD07,and KJ2012Z309)
文摘We propose an efficient scheme for realizing quantum dense coding with three-particle GHZ state in separated low-Q cavities. In this paper, the GHZ state is first prepared with three atoms trapped, respectively, in three spatial separated cavities. Meanwhile, with the assistance of a coherent optical pulse and X-quadrature homodyne measurement, we can im- plement quantum dense coding with three-particle GHZ state with a higher probability. Our scheme can also be generalized to realize N-particle quantum dense coding.
基金Project supported by Youth Foundation of Hubei Province, China （Grant No 2004Q001）, the Key Program of Hubei Province, China （Grant No Z20052201） and Natural Science Foundation of Hubei Province, China （Grant No 2006ABA055）.
文摘Following a recent proposal （Phys. Left. A 346 （2005） 330） about quantum dense coding using a tripartite entangled GHZ state and W state, this paper proposes an experimentally feasible scheme for dense coding in cavity QED by using another peculiar tripartite entangled state. In the scheme the atoms interact simultaneously with a highly detuned cavity mode with the assistance of a classical field, the successful probability of dense coding scheme with this peculiar tripartite entangled state equals 1.
基金supported by the National Natural Science Foundation of China (Grant No 10674001)the Program of Education Department of Anhui University of China (Grant No KJ2007A002)the Youth Program of Fuyang Normal College of China (Grant No 2005LQ04)
文摘An experimentally feasible protocol for realizing dense coding by using a class of W-state in cavity quantum electrodynamics （QED） is proposed in this paper. The prominent advantage of our scheme is that the successful probability of the dense coding with a W-class state can reach 1. In addition, the scheme can be implemented by the present cavity QED techniques.
文摘In this paper, we discuss the concepts of quantum coding and error correction for a five-particle entangled state. Error correction can correct bit-reverse or phase-flip errors of one and two quantum states and is no longer limited to only one quantum state. We encode a single quantum state into a five-particle entangled state before being transferred to the sender. We designed an automatic error-correction circuit to correct errors caused by noise. We also simplify the design process for a multiple quantum error-correction circuit. We compare error-correction schemes for five and three entangled particles in terms of efficiency and capabilities. The results show that error-correction efficiency and fidelity are im- proved.
基金Project supported by the Important Program of Hunan Provincial Education Department (Grant No 06A038)Department of Education of Hunan Province (Grant No 06C080)Hunan Provincial Natural Science Foundation,China (Grant No 06JJ4003)
文摘This paper proposes an experimentally feasible scheme for implementing quantum dense coding of trapped-ion system in decoherence-free states. As the phase changes due to time evolution of components with different eigenenergies of quantum superposition are completely frozen, quantum dense coding based on this model would be perfect. The scheme is insensitive to heating of vibrational mode and Bell states can be exactly distinguished via detecting the ionic state.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10971247 and 10905016)Natural Science Foundation of Hebei Province of China (Grant Nos. F2009000311 and A2010000344)the Science Foundation of Hebei Normal University (Grant No. L2010Q04)
文摘In this paper, we investigate perfect quantum teleportation and dense coding by using an 2N-qubit W state channel. In the quantum teleportation scheme, an unknown N-qubit entangled state can be perfectly teleported. One ebit of entanglement and two bits of classical communication are consumed in the teleportation process, just like when using the Bell state channel. While N ＋ 1 bits of classical information can be transmitted by only sending N particles in the dense coding protocol.
基金Project supported by Anhui Provincial Natural Science Foundation, China （Grant No 03042401）, the Key Program of the Education Department of Anhui Province, China （Grant Nos 2002kj029zd and 2006kj070A）, and the Talent Foundation of Anhui University, China. 0ne of the authors, Xue Zheng-Yuan, is also supported by the Postgraduate Innovation Research Plan from Anhui university, China.
文摘We investigate schemes for quantum secret sharing and quantum dense coding via tripartite entangled states. We present a scheme for sharing classical information via entanglement swapping using two tripartite entangled GHZ states. In order to throw light upon the security affairs of the quantum dense coding protocol, we also suggest a secure quantum dense coding scheme via W state by analogy with the theory of sharing information among involved users.
文摘The paper introduces the state reduction algorithm and accelerated state reduction algorithm are used to compute the distance weight enumerator(transfer function) T[x,y] of convolutional codes.Next use computer simulation to compare upper bound on the bit error probability on an additive white Gaussian noise (AWGN) for maximum free distance (MFD) codes of previously found and optimum distance spectrum (ODS) codes with rate 1/4,overall constraint length are 5 and 7,respectively. Finally,a method of how to search for good convolutional codes is given.
文摘The paper introduces the state reduction algorithm and accelerated state reduction algorithm are used to compute the distance weight enumerator(transfer function)T[x,y] of convolutional codes.Next use computer simulation to compare upper bound on the bit error probability on an additive white Gaussian noise(AWGN) for maximum free distance(MFD) codes of previously found and optimum distance spectrum(ODS) codes with rate 1/4,overall constraint length are 5 and 7,respectively.Finally,a method of how to search for good convolutional codes is given.
基金Supported by the National Natural Science Foundation of China(60673071)
文摘Let C be a free cyclic code over Zp^a and dim pC = k. In the paper, we prove that if the k characteristic generators of C are p-linearly independent then the corresponding nα- k characteristic generators of C^⊥ are p-linearly independent. We then show that to any trellis that can be constructed from k p-linearly independent characteristic generators of C, there exists a trellis for C^⊥ with the same state-complexity profile, which generalizes the conjecture of Koetter and Vardy to a free cyclic code over Zpo.
文摘Wireless information and powered transfer networks(WIPT) has recently been implemented in 5th generation wireless networks. In this paper, we consider half-duplex relaying system in which the energy constrained relay node collects energy via radio frequency(RF) signals from the surrounding resources. Regarding energy harvesting protocol, we propose power time switching-based relaying(PTSR) architecture for both amplify-and-forward(AF) and decode-and-forward(DF). Especially, we reveal the analytical expressions of achievable throughput, ergodic capacity and energy-efficient in case of imperfect channel state information(CSI) for both AF and DF network. Through numerical analysis, we analyse the throughput performance, energy-efficient and ergodic capacity for different parameters, including power splitting ratio and energy harvesting time. Moreover, we also depict the performance comparison between AF and DF network with perfect and imperfect CSI. The results in numerical analysis reveal that the result of AF relaying network is less significant than DF relaying network in the various scenarios.
基金National Natural Science Foundation of China(No.61210306074)Natural Science Foundation of Jiangxi Province,China(No.2012BAB201025)the Scientific Program of Jiangxi Provincial Education Department,China(Nos.GJJ14583,GJJ13008)
文摘It is often necessary to recognize human mouth-states for detecting the number of audio sources and improving the speech recognition capability of an intelligent robot auditory system. A human mouth-state recognition method based on image warping and sparse representation( SR) combined with homotopy is proposed.Using properly warped training mouth-state images as atoms of the overcomplete dictionary overcomes the impact of the diversity of the mouths' scales,shapes and positions so that further improvement of the robustness can be achieved and the requirement for a large number of training samples can be relieved. The homotopy method is employed to compute the expansion coefficients effectively,i. e.,for sparse coding. The orthogonal matching pursuit( OMP) is also tested and compared with the homototy method. Experimental results and comparisons with the state-of-the-art methods have proved the effectiveness of the proposed approach.
基金funded by the EPSRC of UK under Grant EP/I037423/1
文摘Physical-layer network coding （PNC） has the potential to significantly improve the throughput of wireless networks where the channels can be modeled as additive white Gaussian noise （AWGN） channel. As extending to mul- tiple channels, this technique requires both amplitude and phase compensation at each transmitter and will lead to inef- ficient systems yielding no diversity even with perfect channel state information （CSI）. In order to avoid these limita- tions, we apply network coding with diversity （NCD） to achieve a form of selection diversity and extend NCD to coop- erative multiple access channels in this paper. However, in practical wireless communication systems, the CSI could become outdated due to the difference between the CSI used in the relay selection and data transmission phases. Hence, the selected relay may not be the best one during data transmission phase due to the dynamic change in the wireless channels. Therefore, we first explore the relation between the present and past CSIs. Exploiting this relationship, the NCD scheme with outdated CSI is investigated based on the past CSI. To evaluate the performance of this scheme, an information-theoretic metric, namely the outage capacity, is studied under this condition.
