The logic Bell-state which encodes many physical qubits in a logic qubit has great application potential in the future quantum communication field, for it is robust to the decoherence in a noisy environment. In this p...
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The logic Bell-state which encodes many physical qubits in a logic qubit has great application potential in the future quantum communication field, for it is robust to the decoherence in a noisy environment. In this paper, we propose a complete logic Bell-state analysis (LBSA) with the help of the auxiliary single atoms trapped in the low-quality cavity. We construct the parity-check measurement gate based on the photonic Faraday rotation effect and complete the task combined with the Hadamard operation and single-qubit measurement. The number of physical qubits encoded in each logic qubit does not affect the analysis. We also discuss the application of this LBSA in the fields of quantum teleportation and logic-qubit entanglement swapping. Our LBSA protocol may have practical application in future long-distance quantum communication.
Image registration based on mutual information is widely employed in medical image processing. But this method may lead to the wrong result of registration due to the excessive local maximum points and low accuracy. A...
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In orthogonal frequency division multiple access (OFDMA)-based cellular networks subject to the distance-dependent path loss and shadow fading (SF), the downlink inter-cell interference (ICI) for a given user equipmen...
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ISBN:
(纸本)9781467364300
In orthogonal frequency division multiple access (OFDMA)-based cellular networks subject to the distance-dependent path loss and shadow fading (SF), the downlink inter-cell interference (ICI) for a given user equipment (UE) is essentially a sum of several lognormal random variables (RVs). So far, no method of approximating the lognormal sum distribution is explicitly accurate when the component lognormal RVs with different logarithmic means and logarithmic variances are correlated. In this paper, the Normal Inverse Gaussian (NIG) distribution is proposed to approximate the downlink ICI for a given UE with the correlated SF. First, the downlink ICI is modelled as a sum of several correlated lognormal RVs. Then original moments of the lognormal sum in the logarithmic domain are obtained analytically. Finally the estimated parameters of the NIG distribution are computed explicitly by the mean, variance, skewness and kurtosis of the lognormal sum in the logarithmic domain through moment matching. Numerical results verify the accuracy of the NIG approximation when the correlated component lognormal RVs have different logarithmic means and logarithmic variances, and show that the NIG approximation outperforms the MGF-based lognormal approximation in various scenarios.
We present a scheme for the practical decoy-state quantum key distribution with heralded single-photon source. In this scheme, only two-intensity decoy states are employed. However, its performance can approach the as...
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We present a scheme for the practical decoy-state quantum key distribution with heralded single-photon source. In this scheme, only two-intensity decoy states are employed. However, its performance can approach the asymptotic case of using infinite decoy states. We compare it with the standard three-intensity decoy-state method, and through numerical simulations, we demonstrate its significant improvement over the three-intensity method in both the final key rate and the secure transmission distance. Furthermore, when taking statistical fluctuations into account, a very high key generation rate can still be obtained even at a long transmission distance.
In the view of the DV-Hop positioning algorithm which relies on the distance vector and beacon nodes, several aspects are improved: the average hop distance and hop count are corrected;a method to detect the abnormal ...
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In the view of the DV-Hop positioning algorithm which relies on the distance vector and beacon nodes, several aspects are improved: the average hop distance and hop count are corrected;a method to detect the abnormal distribution of beacon nodes is used to avoid the influence of the abnormal distribution on the positioning performance. The proposed algorithm is simple and effective. Simulation results show that compared with the traditional DV-Hop algorithm, the performance of the proposed algorithm is greatly *** performance is even even superior to that of the algorithm mentioned in literature [10]
We propose an efficient entanglement concentration protocol (ECP) based on electron-spin cluster states assisted with single electrons. In the ECP, we adopt the electron polarization beam splitter (PBS) and the ch...
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We propose an efficient entanglement concentration protocol (ECP) based on electron-spin cluster states assisted with single electrons. In the ECP, we adopt the electron polarization beam splitter (PBS) and the charge detector to construct the quantum nondemolition measurement. According to the result of the measurement of the charge detection, we can ultimately obtain the maximally entangled cluster states. Moreover, the discarded items can be reused in the next round to reach a high success probability. This ECP may be useful in current solid quantum computation.
Since the temporal and spatial correlations of sensor readings are existent in wirelesssensornetworks (WSNs), this paper develops a clustered spatio-temporal compression scheme by integrating network coding (NC) and...
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Since the temporal and spatial correlations of sensor readings are existent in wirelesssensornetworks (WSNs), this paper develops a clustered spatio-temporal compression scheme by integrating network coding (NC) and compressed sensing (CS) for correlated data. The proper selections of NC coefficients and measurement matrix are designed for this scheme. This design guarantees the reconstruction of clustered compression data successfully with an overwhelming probability and unifies the operations of NC and CS into real field successfully. Moreover, in contrast to other spatio-temporal schemes with the same computational complexity, the proposed scheme possesses lower reconstruction error by employing the independent encoding in each sensor node (including the cluster head nodes) and joint decoding in sink node. At the same time it has lower computational complexity as compared with JSM-based spatio-temporal scheme by exploiting the temporal and spatial correlations of original sensing data step by step. Finally, the simulation results verify that the clustered spatio-temporal compression scheme outperforms the other two compression schemes significantly in terms of recovery error and compression gain.
In order to take advantage of the asynchronous sensing information, alleviate the sensing overhead of secondary users (SUs) and improve the detection performance, a sensor node-assisted asynchronous cooperative spec...
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In order to take advantage of the asynchronous sensing information, alleviate the sensing overhead of secondary users (SUs) and improve the detection performance, a sensor node-assisted asynchronous cooperative spectrum sensing (SN-ACSS) scheme for cognitive radio (CR) network (CRN) was proposed. In SN-ACSS, each SU is surrounded by sensor nodes (SNs), which asynchronously make hard decisions and soft decisions based on the Bayesian fusion rule instead of the SU. The SU combines these soft decisions and makes the local soft decision. Finally, the fusion center (FC) fuses the local soft decisions transmitted from SUs with different weight coefficients to attain the final soft decision. Besides, the impact of the statistics of licensed band occupancy on detection performance and the fact that different SNs have different sensing contributions are also considered in SN-ACSS scheme. Numerical results show that compared with the conventional synchronous cooperative spectrum sensing (SCSS) and the existing ACSS schemes, SN-ACSS algorithm achieves a better detection performance and lower cost with the same number of SNs.
An entangled coherent state (ECS) is one type of entanglement, which is widely discussed in the application of quan- tum information processing (QIP). In this paper, we propose an entanglement concentration protoc...
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An entangled coherent state (ECS) is one type of entanglement, which is widely discussed in the application of quan- tum information processing (QIP). In this paper, we propose an entanglement concentration protocol (ECP) to distill the maximally entangled W-type ECS from the partially entangled W-type ECS. In the ECP, we adopt the balanced beam split- ter (BS) to make the parity check measurement. Our ECP is quite different from the conventional ECPs. After performing the ECP, not only can we obtain the maximally entangled ECS with some success probability, but also we can increase the amplitude of the coherent state. Therefore, it is especially useful in long-distance quantum communication, if the photon loss is considered.
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