Discrete modulation continuous-variable quantum key distribution based on quantum catalysis

Ye, Wei; Guo, Ying; Xia, Ying; Zhong, Hai; Zhang, Huan; Ding, Jianzhi; Hu, Li-Yun

doi:10.7498/aps.69.20191689

Cited by 21 publications

(7 citation statements)

References 24 publications

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“…For example, the parity detection has been proved to be an optimal detection for linear phase estimation in lots of schemes [27,51]. Compared with both intensity and parity detections, however, homodyne detection can be easily realized with current technologies, thereby playing a key role in the field of continuous-variable quantum key distribution (CV-QKD) [52][53][54][55][56]. Therefore, in our scheme the homodyne detection is employed on mode a at one of output port to estimate the phase parameter φ, where the detected variable is the amplitude quadrature X, i.e.,…”

Section: Phase Sensitivity Via Homodyne Detectionmentioning

confidence: 99%

Improvement of phase sensitivity in SU(1,1) interferometer via a Kerr nonlinear

Chang¹,

Ye²,

Zhang³

et al. 2021

Preprint

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We propose a theoretical scheme to enhance the phase sensitivity by introducing a Kerr nonlinear phase shift into the traditional SU(1,1) interferometer with a coherent state input and homodyne detection. We investigate the realistic effects of photon losses on phase sensitivity and quantum Fisher information. The results show that compared with the linear phase shift in SU(1,1) interferometer, the Kerr nonlinear case can not only enhance the phase sensitivity and quantum Fisher information, but also significantly suppress the photon losses. We also observe that at the same accessible parameters, internal losses have a greater influence on the phase sensitivity than the external ones. It is interesting that, our scheme shows an obvious advantage of low-cost input resources to obtain higher phase sensitivity and larger quantum Fisher information due to the introduction of nonlinear phase element.

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Section: Phase Sensitivity Via Homodyne Detectionmentioning

confidence: 99%

Improvement of phase sensitivity in SU(1,1) interferometer via a Kerr nonlinear

Chang¹,

Ye²,

Zhang³

et al. 2021

Preprint

Self Cite

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show abstract

“…More strikingly, the single-phase estimation with the QCRB in the presence of noisy environments, e.g., photon loss [17][18][19], phase diffusion [20,21], and thermal noise [22,23], can be tackled using the variational method [17,20] pro-posed by Escher, greatly promoting the practical applications of quantum metrology [24][25][26]. On the other hand, extending toward the multiple phase estimation with the QCRB has attracted considerable interest more recently, thereby resulting in the potential applications [27][28][29][30][31][32][33][34], such as quantum-enhanced sensor network [29][30][31][32] and optical imaging [33,34]. Moreover, in order to improve the precision of multiple-phase estimation, multimode NOON (or NOON-like) states [35][36][37][38][39], generalized entangled coherent states [40] and multimode Gaussian states [41] have been considered, even in the presence of noisy environment [42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous multiple angular displacement estimation precision enhanced by the intramode correlation

Chang¹,

Ye²,

Rao³

et al. 2022

Preprint

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The angular displacement estimation is one of significant branches of quantum parameter estimation. However, most of the studies have focused on the single-angular displacement estimation, while the multiple angular displacement estimation in ideal and noisy scenarios is still elusive. In this paper, we investigate the simultaneous multiple angular displacement estimation based on an orbital angular momentum (OAM), together with inputting (d + 1)-mode NOON-like states as the probe state. By revealing the role of the intramode correlation of the probe state, this allows us to give a reasonable explanation for the corresponding quantum Cramér-Rao bound (QCRB) behaviors with and without photon losses. Our analyses suggest that the QCRB for the multiple angular displacement estimation is always positively related to the intramode correlation, especially for the multimode entangled squeezed vacuum state showing the best performance compared to another probe state. More importantly, strengthening the robustness of multiple angular-displacement estimation systems can be achieved by increasing the OAM quantum number.

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“…They found that for all attained states, only the photon-subtracted and photon-addedthen-subtracted states can perform better than the original TMSV in terms of the entanglement improvement. In addition to these conventional non-Gaussian operations, the usages of the quantum catalysis [20,24] and the quantum scissor [19,32] are other feasible ways to improve the nonclassicality and entanglement of quantum states, which makes them play an important role in realizing the long-distance quantum communication [33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Nonclassicality and entanglement properties of non-Gaussian entangled states via a superposition of number-conserving operations

Guo

Zhang

et al. 2020

Quantum Inf Process

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We theoretically investigate the nonclassicality and entanglement properties of non-Gaussian entangled states generated by using a number-conserving generalized superposition of products (GSP), i.e., saa † + ta † a m with s 2 + t 2 = 1 on each mode of an input two-mode squeezed coherent (TMSC) state. The simulation results show that, compared to the typical two-mode squeezed vacuum state, the usage of small coherent amplitude is conductive to offering an opportunity for not only effectively enhancing the nonclassicality in terms of antibunching effect and Wigner function, but also significantly improving the entanglement quantified by Einstein-Podolsky-Rosen correlation and Hillery-Zubairy correlation. For the increase of the number of operations, the region of both the existing antibunching effect and the improved entanglement decreases, but this region of the improved teleportation fidelity and the negative distribution of the Wigner function is on the increase. Under an ideal Braunstein and Kimble teleportation protocol, when the generated states are treated as an entangled resource, the optimal teleportation fidelity can be achieved by taking a suitable squeezing parameter and the number of operations for the optimal choices of s. In order to highlight the advantages of the use of the GSP-embedded TMSC, under the same parameters, we also make a comparison about the performances of both the entanglement and the fidelity for different non-Gaussian entangled states, involving the photon-subtracted-then-added TMSC states and the photon-added-thensubtracted TMSC states. It is found that in the regime of small squeezing values, both of the entanglement and the fidelity for the generated states can perform better than the other cases.

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Discrete modulation continuous-variable quantum key distribution based on quantum catalysis

Cited by 21 publications

References 24 publications

Improvement of phase sensitivity in SU(1,1) interferometer via a Kerr nonlinear

Improvement of phase sensitivity in SU(1,1) interferometer via a Kerr nonlinear

Simultaneous multiple angular displacement estimation precision enhanced by the intramode correlation

Nonclassicality and entanglement properties of non-Gaussian entangled states via a superposition of number-conserving operations

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