Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2210.01471 · Optics Express

Bound for Gaussian-state quantum illumination using a direct photon measurement

Su‐Yong Lee, Dong Hwan Kim, Yonggi Jo, Taek Jeong, Zaeill Kim, Duk Y. Kim

Published Oct 20, 2023• 7 citations
arXivHTMLPDF

Abstract

It is important to find feasible measurement bounds for quantum information protocols. We present analytic bounds for quantum illumination with Gaussian states when using an on-off detection or a photon number resolving (PNR) detection, where its performance is evaluated with signal-to-noise ratio. First, for coincidence counting measurement, the best performance is given by the two-mode squeezed vacuum (TMSV) state which outperforms the coherent state and the classically correlated thermal (CCT) state. However, the coherent state can beat the TMSV state with increasing signal mean photon number in the case of the on-off detection. Second, the performance is enhanced by taking Fisher information approach with all counting probabilities including non-detection events. In the Fisher information approach, the TMSV state still presents the best performance but the CCT state can beat the TMSV state with increasing signal mean photon number in the case of the on-off detection. Furthermore, we show that it is useful to take the PNR detection on the signal mode and the on-off detection on the idler mode, which reaches similar performance of using PNR detection on both modes.

DOI
10.1364/oe.505405

Related papers

Observable bound for Gaussian illumination

Su‐Yong Lee, Yonggi Jo, Taek Jeong +6 more

We propose observable bounds for Gaussian illumination to maximize the signal-to-noise ratio, which minimizes the discrimination error between the presence and absence of a low-reflectivity target using Gaussian states. The observable bounds are achieved with mode-by-mode measurements. In the quantum regime using a two-mode squeezed vacuum state, our observable receiver outperforms the other feasible receivers whereas it cannot approach the quantum Chernoff bound. The corresponding observable cannot be implemented with heterodyne detections due to the additional vacuum noise. In the classical regime using a thermal state, a receiver implemented with a photon number difference measurement approaches its bound regardless of the signal mean photon number, while it asymptotically approaches the classical bound in the limit of a huge idler mean photon number.

arXiv:2106.12109•Physical Review A•Apr 8, 2022•14 citations

Quantum illumination using non-Gaussian states with conditional measurements

Huan Zhang, Ying Xia, Wei Ye +2 more

Quantum illumination is a quantum sensing protocol primarily used for object detection, which aims to detect the presence of a target with low reflectivity in the free space using quantum light fields. Here we investigate a quantum illumination scheme using an entangled light source by performing non-Gaussian operations on the two-mode squeezed vacuum (TMSV) state in order to reduce the detection error probability and meanwhile improve the signal-to-noise (SNR) ratio. We demonstrate that under the same squeezing parameter, the non-Gaussian operations can significantly reduce the detection error rate compared with the original TMSV state. Under the same average signal photon number, both the TMSV states with and without non-Gaussian operations can provide smaller error rate than that of the coherent state. In addition, we consider the balanced homodyne detection on idler and return signal photons as joint measurement and find that non-Gaussian operations can enhance the SNR of target detection by about 6--9 dB compared with that using TMSV. These results here demonstrate the advantage of the non-Gaussian entangled source in quantum illumination protocol and can find potential applications in target detection in noisy environment.

Physical Review A•Jun 28, 2024•12 citations

Optimal observables for Gaussian illumination

Su‐Yong Lee, Yonggi Jo, Taek Jeong +6 more

We propose optimal observables for Gaussian illumination to maximize the signal-to-noise ratio, which minimizes the discrimination error between the presence and absence of a low-reflectivity target using Gaussian states. The optimal observables dominantly consist of off-diagonal components of output states, which is implemented with feasible setups. In the quantum regime using a two-mode squeezed vacuum state, the receiver implemented with heterodyne detections outperforms the other feasible receivers, which asymptotically improves the error probability exponent by a factor of two over the classical state bound. In the classical regime using coherent or thermal states, the receiver implemented with photon number difference measurement asymptotically approaches its bound.

•Jun 23, 2021•0 citations

Quantum illumination using non-Gaussian states generated by photon subtraction and photon addition

Longfei Fan, Muhammad Suhail Zubairy

Quantum illumination takes advantage of quantum entanglement to achieve low error probability for detecting a low reflective object embedded in a noisy thermal bath. The two-mode squeezed state (TMSS), which is a Gaussian state, has been applied to quantum illumination as the detecting states in experiment. The photon-subtracted TMSS has also been proposed to achieve even lower error probability. Here we study quantum illumination with non-Gaussian states generated by photon subtraction and photon addition. Helstrom limit and quantum Chernoff bound are evaluated for comparison between performance of states with the same squeezing strength and with the same signal strength, respectively. Particularly, states generated by asymmetrical coherent superposition of photon subtraction and addition are studied, which are shown by us to have better performance than symmetrical ones. We show that non-Gaussian operations enhance the quantum illumination by introducing both stronger entanglement and signal strength. We then give a strategy on how to choose the optimal states for the best performance in different scenarios.

Physical Review A•Jul 17, 2018•62 citations

Gaussian quantum illumination via monotone metrics

Dong Hwan Kim, Yonggi Jo, Duk Y. Kim +5 more

Quantum illumination is to discern the presence or absence of a target, where the error probability decays exponentially in the number of copies used. When the target reflectivity is small, the exponential decay constant can be computed using monotone metrics. We explicitly derive analytic formula for the decay constant of an arbitrary Gaussian input state in terms of first- and second-order moments assuming a low reflectivity target. Especially, further assuming large background noise, there is no need of symplectic diagonalization, which highly complicates the computation of decay constants. First, we show that the performance of a displaced two-mode squeezed vacuum (TMSV) state with low squeezing can be similar to that of a TMSV state with high squeezing. Second, we show that it is of utmost importance to prepare an efficient idler memory to outperform coherent states while providing a criterion on the idler memory transmittivity. Finally, we identify the region of physically possible correlations between the signal and idler modes that can outperform coherent states.

arXiv:2302.07498•Physical Review Research•Jul 6, 2023•5 citations

Quantum illumination with non-Gaussian states: Bounds on the minimum error probability using quantum Fisher information

Changsuk Noh, Changhyoup Lee, Su‐Yong Lee

Quantum illumination employs entangled states to detect a weakly reflective target in a thermal bath. The performance of a given entangled state is evaluated from the minimum error probability in the asymptotic limit, which is compared against the optimal coherent state scheme. We derive an upper bound as well as a lower bound on the asymptotic minimum error probability, as functions of the quantum Fisher information. The upper bound can be achieved using a repetitive local strategy. This allows us to compare the optimal performance of definite-photon-number entangled states against that of the coherent states under local strategies. When optimized under the constraint of a fixed total energy, we find that a coherent state outperforms the definite-photon-number entangled state with the same signal energy.

arXiv:2110.06891•Oct 13, 2021•1 citation
It is important to find feasible measurement bounds for quantum information protocols. We present analytic bounds for quantum illumination with Gaussian states when using an on-off detection or a photon number resolving (PNR) detection, where its performance is evaluated with signal-to-noise ratio. First, for coincidence counting measurement, the best performance is given by the two-mode squeezed vacuum (TMSV) state which outperforms the coherent state and the classically correlated thermal (CCT) state. However, the coherent state can beat the TMSV state with increasing signal mean photon number in the case of the on-off detection. Second, the performance is enhanced by taking Fisher information approach with all counting probabilities including non-detection events. In the Fisher information approach, the TMSV state still presents the best performance but the CCT state can beat the TMSV state with increasing signal mean photon number in the case of the on-off detection. Furthermore, we show that it is useful to take the PNR detection on the signal mode and the on-off detection on the idler mode, which reaches similar performance of using PNR detection on both modes.
We propose observable bounds for Gaussian illumination to maximize the signal-to-noise ratio, which minimizes the discrimination error between the presence and absence of a low-reflectivity target using Gaussian states. The observable bounds are achieved with mode-by-mode measurements. In the quantum regime using a two-mode squeezed vacuum state, our observable receiver outperforms the other feasible receivers whereas it cannot approach the quantum Chernoff bound. The corresponding observable cannot be implemented with heterodyne detections due to the additional vacuum noise. In the classical regime using a thermal state, a receiver implemented with a photon number difference measurement approaches its bound regardless of the signal mean photon number, while it asymptotically approaches the classical bound in the limit of a huge idler mean photon number.
Quantum illumination is a quantum sensing protocol primarily used for object detection, which aims to detect the presence of a target with low reflectivity in the free space using quantum light fields. Here we investigate a quantum illumination scheme using an entangled light source by performing non-Gaussian operations on the two-mode squeezed vacuum (TMSV) state in order to reduce the detection error probability and meanwhile improve the signal-to-noise (SNR) ratio. We demonstrate that under the same squeezing parameter, the non-Gaussian operations can significantly reduce the detection error rate compared with the original TMSV state. Under the same average signal photon number, both the TMSV states with and without non-Gaussian operations can provide smaller error rate than that of the coherent state. In addition, we consider the balanced homodyne detection on idler and return signal photons as joint measurement and find that non-Gaussian operations can enhance the SNR of target detection by about 6--9 dB compared with that using TMSV. These results here demonstrate the advantage of the non-Gaussian entangled source in quantum illumination protocol and can find potential applications in target detection in noisy environment.
We propose optimal observables for Gaussian illumination to maximize the signal-to-noise ratio, which minimizes the discrimination error between the presence and absence of a low-reflectivity target using Gaussian states. The optimal observables dominantly consist of off-diagonal components of output states, which is implemented with feasible setups. In the quantum regime using a two-mode squeezed vacuum state, the receiver implemented with heterodyne detections outperforms the other feasible receivers, which asymptotically improves the error probability exponent by a factor of two over the classical state bound. In the classical regime using coherent or thermal states, the receiver implemented with photon number difference measurement asymptotically approaches its bound.
Quantum illumination takes advantage of quantum entanglement to achieve low error probability for detecting a low reflective object embedded in a noisy thermal bath. The two-mode squeezed state (TMSS), which is a Gaussian state, has been applied to quantum illumination as the detecting states in experiment. The photon-subtracted TMSS has also been proposed to achieve even lower error probability. Here we study quantum illumination with non-Gaussian states generated by photon subtraction and photon addition. Helstrom limit and quantum Chernoff bound are evaluated for comparison between performance of states with the same squeezing strength and with the same signal strength, respectively. Particularly, states generated by asymmetrical coherent superposition of photon subtraction and addition are studied, which are shown by us to have better performance than symmetrical ones. We show that non-Gaussian operations enhance the quantum illumination by introducing both stronger entanglement and signal strength. We then give a strategy on how to choose the optimal states for the best performance in different scenarios.
Quantum illumination is to discern the presence or absence of a target, where the error probability decays exponentially in the number of copies used. When the target reflectivity is small, the exponential decay constant can be computed using monotone metrics. We explicitly derive analytic formula for the decay constant of an arbitrary Gaussian input state in terms of first- and second-order moments assuming a low reflectivity target. Especially, further assuming large background noise, there is no need of symplectic diagonalization, which highly complicates the computation of decay constants. First, we show that the performance of a displaced two-mode squeezed vacuum (TMSV) state with low squeezing can be similar to that of a TMSV state with high squeezing. Second, we show that it is of utmost importance to prepare an efficient idler memory to outperform coherent states while providing a criterion on the idler memory transmittivity. Finally, we identify the region of physically possible correlations between the signal and idler modes that can outperform coherent states.
Quantum illumination employs entangled states to detect a weakly reflective target in a thermal bath. The performance of a given entangled state is evaluated from the minimum error probability in the asymptotic limit, which is compared against the optimal coherent state scheme. We derive an upper bound as well as a lower bound on the asymptotic minimum error probability, as functions of the quantum Fisher information. The upper bound can be achieved using a repetitive local strategy. This allows us to compare the optimal performance of definite-photon-number entangled states against that of the coherent states under local strategies. When optimized under the constraint of a fixed total energy, we find that a coherent state outperforms the definite-photon-number entangled state with the same signal energy.