pith. sign in

arxiv: 2503.08248 · v2 · submitted 2025-03-11 · 🪐 quant-ph

Quantum illumination with nonzero-mean signal-idler states via noise-enhanced heterodyne work extraction

Mustafa G\"undogan , Mehmet Emre Tasgin This is my paper

Pith reviewed 2026-05-23 00:42 UTC · model grok-4.3

classification 🪐 quant-ph
keywords quantum illuminationheterodyne detectionwork extractiontwo-mode squeezed statesChernoff exponentmicrowave sensingthermal noisenonzero-mean states
0
0 comments X

The pith

A heterodyne work-extraction receiver on noisy two-mode-squeezed states yields a Chernoff exponent linear in target transmissivity, matching ideal OPA performance in the weak-return regime.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper introduces a quantum-illumination receiver that measures the returned mode with heterodyne detection and feeds the outcome forward to displace a stored idler for work extraction. This converts second-order correlations into a measurable first-moment signal. For noisy two-mode-squeezed resources the scheme is governed by the correlation parameter x_h, which produces a Chernoff exponent linear in transmissivity when background noise dominates. The approach works with states that carry nonzero means and directly uses preparation noise, without requiring zero first moments or nonlinear detection.

Core claim

For a noisy two-mode-squeezed resource the calibrated displaced-idler work score has Chernoff exponent ξ_h = x_h/4 + O(x_h²), with x_h = η c² / [a(b + ν_h)], which becomes linear in the target transmissivity η in the weak-return, background-dominated regime, matching the leading-order performance of an ideal OPA receiver but achieved here via a linear and directly measurable correlation mechanism. Unlike OPA-based schemes, the protocol does not require zero first moments and harnesses preparation noise when correlated prior to transmission.

What carries the argument

The heterodyne correlation parameter x_h = η c² / [a(b + ν_h)] that sets the work-score Chernoff exponent for the displaced idler.

Load-bearing premise

The noisy two-mode-squeezed resource maintains the stated correlation structure and the idler displacement plus work extraction incur no extra loss or decoherence that would invalidate x_h.

What would settle it

An experiment in which the measured Chernoff exponent of the work score deviates from x_h/4 (plus higher-order terms) when transmissivity is small and background dominates.

Figures

Figures reproduced from arXiv: 2503.08248 by Mehmet Emre Tasgin, Mustafa G\"undogan.

Figure 1
Figure 1. Figure 1: FIG. 1. Extracted work increases as preparation noise [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
read the original abstract

Room temperature microwave and low-THz links exhibit large thermal occupations, making phase sensitive signal-idler correlations difficult to recover after loss. We introduce a work-extraction-based quantum-illumination receiver in which the returned mode $\hat{a}_R$ is measured via heterodyne detection and the outcome is fed forward to a locally stored, possibly displaced idler. For a noisy two-mode-squeezed resource, the receiver is characterized by the heterodyne correlation parameter $x_{\rm h}=\eta c^2/[a(b+\nu_{\rm h})]$. The calibrated displaced-idler work score has Chernoff exponent $\xi_{\rm h}=x_{\rm h}/4+O(x_{\rm h}^2)$, which becomes linear in the target transmissivity $\eta$ in the weak-return, background-dominated regime, matching the leading-order performance of an ideal OPA receiver, but achieved here via a linear and directly measurable correlation mechanism. Unlike OPA-based schemes, the present protocol does not require zero first moments and does not rely on weak-probability nonlinear detection. In our scheme, extracted work converts hard-to-measure second order moment correlation information into an accessible first moment signal. Moreover, preparation noise $\bar{n}_p$, naturally present at room temperature in the microwave and THz regimes, can be directly harnessed when correlated prior to transmission, whereas a classical coherent signal cannot utilize such incoherent thermal photons without first converting them into usable signal energy.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 2 minor

Summary. The manuscript proposes a quantum illumination receiver for high-thermal-noise regimes that performs heterodyne detection on the returned signal mode and uses the outcome to displace a locally stored idler for work extraction. For a noisy two-mode-squeezed resource with parameters a, b, c, it defines the heterodyne correlation parameter x_h = η c² / [a(b + ν_h)] and derives the Chernoff exponent ξ_h = x_h/4 + O(x_h²). This yields leading-order linear scaling in target transmissivity η in the weak-return, background-dominated regime, matching the performance of an ideal OPA receiver but via a linear, directly measurable correlation mechanism that can harness preparation noise without requiring zero first moments or nonlinear detection.

Significance. If the derivation holds under the stated model, the protocol provides a practical alternative for microwave/THz quantum illumination by converting hard-to-measure second-order correlations into an accessible first-moment work signal. A notable strength is the explicit use of preparation noise as a resource when correlated prior to transmission, which classical coherent signals cannot exploit without conversion losses. The linear mechanism and parameter definitions (a, b, c) are clearly articulated.

major comments (1)
  1. [Model and derivation of x_h and ξ_h (around the definition following Eq. for x_h)] The central equality ξ_h = x_h/4 + O(x_h²) and its linearity in η are derived under the assumption of an ideal noisy TMS resource with exact (a, b, c) correlations and lossless idler storage/displacement that preserves the definition of x_h and ν_h. The manuscript should state explicitly whether robustness to small additional thermal noise or loss on the idler arm (which would increase effective ν_h or reduce c) has been checked, as this directly affects the claimed prefactor 1/4 and the equivalence to OPA performance.
minor comments (2)
  1. [Receiver description] Clarify the precise definition of the work-extraction map and the calibration of the displaced-idler score in the main text, including any dependence on the heterodyne outcome distribution.
  2. [Chernoff exponent derivation] The O(x_h²) term is stated but its coefficient or bounding is not shown; adding a brief expansion or numerical check for small x_h would strengthen the leading-order claim.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the positive assessment and the constructive comment on the model assumptions. We address the point below and will incorporate a clarification in the revised manuscript.

read point-by-point responses

  1. Referee: The central equality ξ_h = x_h/4 + O(x_h²) and its linearity in η are derived under the assumption of an ideal noisy TMS resource with exact (a, b, c) correlations and lossless idler storage/displacement that preserves the definition of x_h and ν_h. The manuscript should state explicitly whether robustness to small additional thermal noise or loss on the idler arm (which would increase effective ν_h or reduce c) has been checked, as this directly affects the claimed prefactor 1/4 and the equivalence to OPA performance.

    Authors: We agree that the derivation relies on the ideal idler model (lossless storage and no extra noise beyond the defined ν_h). The manuscript does not contain explicit checks or simulations of additional idler thermal noise or loss. From the explicit form x_h = η c² / [a(b + ν_h)], any increase in effective ν_h or reduction in c would scale x_h downward and thereby reduce the leading coefficient of ξ_h below 1/4. We will add a sentence in the revised text (near the definition of x_h) stating that the prefactor 1/4 and the equivalence to ideal OPA performance hold only under the stated ideal-idler assumption, and that non-ideal idler conditions would degrade performance proportionally to the change in ν_h or c. This clarification does not alter the main claim of linear-in-η scaling for the ideal protocol. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation is self-contained from stated model parameters

full rationale

The paper defines the correlation parameter x_h directly from the noisy TMS resource parameters (a, b, c) and transmissivity η, then states that the Chernoff exponent follows as ξ_h = x_h/4 + O(x_h²) via the heterodyne-plus-work-extraction protocol. This is a forward derivation from the joint state and measurement map, not a reduction of the claimed performance back to the input by construction or by self-citation. No load-bearing step invokes a prior result from the same authors to forbid alternatives, nor renames a known empirical pattern, nor treats a fitted quantity as a prediction. The model assumptions (ideal preparation and lossless idler storage) are explicit modeling choices whose validity is external to the derivation chain itself.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on the two-mode squeezed state model with parameters a, b, c and the definition of the heterodyne correlation x_h; no free parameters are explicitly fitted to data in the abstract, and no new entities are postulated.

axioms (1)
  • domain assumption The resource is a noisy two-mode-squeezed state whose correlation structure is captured by the parameter x_h = η c² / [a(b + ν_h)]
    Invoked to characterize the receiver performance in the abstract.

pith-pipeline@v0.9.0 · 5792 in / 1396 out tokens · 42509 ms · 2026-05-23T00:42:39.609627+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

30 extracted references · 30 canonical work pages

  1. [1]

    One needs to distinguish between pres- ence (hypothesis 1, ˆaR = √η ˆaS + √1 − η ˆach) and (hy- 4 pothesis 0, ˆaR = ˆach)

    The inten- sity difference of the two output modes ˆI = ˆb† +ˆb+ −ˆb† −ˆb− is measured [10]. One needs to distinguish between pres- ence (hypothesis 1, ˆaR = √η ˆaS + √1 − η ˆach) and (hy- 4 pothesis 0, ˆaR = ˆach). The SNR for QI is SNRQI = 4(⟨ˆI⟩1 − ⟨ ˆI⟩0)2 q ⟨∆ˆI⟩1 + q ⟨∆ˆI⟩0 2 , (10) where subscripts stand for the hypothesis number. In the hypothesis...

    work page

  2. [2]

    S.-H. Tan, B. I. Erkmen, V. Giovannetti, S. Guha, S. Lloyd, L. Maccone, S. Pirandola, and J. H. Shapiro, Quantum illumination with gaussian states, Physical Re- view Letters 101, 253601 (2008)

    work page 2008

  3. [3]

    Zhuang, Quantum ranging with gaussian entangle- ment, Physical Review Letters 126, 240501 (2021)

    Q. Zhuang, Quantum ranging with gaussian entangle- ment, Physical Review Letters 126, 240501 (2021)

    work page 2021

  4. [4]

    R. G. Torrom´ e and S. Barzanjeh, Advances in quantum radar and quantum lidar, Progress in Quantum Electron- ics 93, 100497 (2024)

    work page 2024

  5. [5]

    Pirandola, U

    S. Pirandola, U. L. Andersen, L. Banchi, M. Berta, D. Bunandar, R. Colbeck, D. Englund, T. Gehring, C. Lupo, C. Ottaviani, J. L. Pereira, M. Razavi, J. S. Shaari, M. Tomamichel, V. C. Usenko, G. Vallone, P. Vil- loresi, and P. Wallden, Advances in quantum cryptogra- phy, Adv. Opt. Photon. 12, 1012 (2020)

    work page 2020

  6. [6]

    T. C. Ralph, Continuous variable quantum cryptography, Physical Review A 61, 010303 (1999)

    work page 1999

  7. [7]

    S. L. Braunstein and P. Van Loock, Quantum infor- mation with continuous variables, Reviews of Modern Physics 77, 513 (2005)

    work page 2005

  8. [8]

    K. G. Fedorov, M. Renger, S. Pogorzalek, R. Di Candia, Q. Chen, Y. Nojiri, K. Inomata, Y. Nakamura, M. Par- tanen, A. Marx, et al. , Experimental quantum telepor- tation of propagating microwaves, Science Advances 7, eabk0891 (2021)

    work page 2021

  9. [9]

    Pogorzalek, K

    S. Pogorzalek, K. Fedorov, M. Xu, A. Parra-Rodriguez, M. Sanz, M. Fischer, E. Xie, K. Inomata, Y. Nakamura, E. Solano, et al. , Secure quantum remote state prepara- tion of squeezed microwave states, Nature Communica- tions 10, 2604 (2019)

    work page 2019

  10. [10]

    Barzanjeh, S

    S. Barzanjeh, S. Pirandola, D. Vitali, and J. M. Fink, Microwave quantum illumination using a digital receiver, Science advances 6, eabb0451 (2020)

    work page 2020

  11. [11]

    Barzanjeh, S

    S. Barzanjeh, S. Guha, C. Weedbrook, D. Vitali, J. H. 5 Shapiro, and S. Pirandola, Microwave quantum illumina- tion, Physical review letters 114, 080503 (2015)

    work page 2015

  12. [12]

    Fesquet, F

    F. Fesquet, F. Kronowetter, M. Renger, W. K. Yam, S. Gandorfer, K. Inomata, Y. Nakamura, A. Marx, R. Gross, and K. G. Fedorov, Demonstration of mi- crowave single-shot quantum key distribution, Nature Communications 15, 7544 (2024)

    work page 2024

  13. [13]

    A. N. Oruganti, I. Derkach, R. Filip, and V. C. Usenko, Continuous-variable quantum key distribution with noisy squeezed states, Quantum Science and Tech- nology (2025)

    work page 2025

  14. [14]

    Fesquet, F

    F. Fesquet, F. Kronowetter, M. Renger, Q. Chen, K. Honasoge, O. Gargiulo, Y. Nojiri, A. Marx, F. Deppe, R. Gross, et al. , Perspectives of microwave quantum key distribution in the open air, Physical Review A 108, 032607 (2023)

    work page 2023

  15. [15]

    N. J. Cerf, M. Levy, and G. Van Assche, Quantum distri- bution of gaussian keys using squeezed states, Physical Review A 63, 052311 (2001)

    work page 2001

  16. [16]

    Derkach, V

    I. Derkach, V. C. Usenko, and R. Filip, Squeezing- enhanced quantum key distribution over atmospheric channels, New Journal of Physics 22, 053006 (2020)

    work page 2020

  17. [17]

    [11] if the noise were added after the JPA, it would not increase codebook variance though still could provide extra security agains eaves- dropping

    One should note that in Ref. [11] if the noise were added after the JPA, it would not increase codebook variance though still could provide extra security agains eaves- dropping. For instance, in Ref. [13], containing similar authors with Ref. [11], the noise is added after the squeez- ing process. This is indicated in Eqs. (A12) and (A8) in Ref. [13, 27]...

    work page

  18. [18]

    Oppenheim, M

    J. Oppenheim, M. Horodecki, P. Horodecki, and R. Horodecki, Thermodynamical approach to quantify- ing quantum correlations, Physical Review Letters 89, 180402 (2002)

    work page 2002

  19. [19]

    Brunelli, M

    M. Brunelli, M. G. Genoni, M. Barbieri, and M. Pater- nostro, Detecting gaussian entanglement via extractable work, Physical Review A 96, 062311 (2017)

    work page 2017

  20. [20]

    Entanglement is measured in by logarithmic- negativity Ecal = max(0 , log ν−) [28, 29] and becomes larger as ν− gets smaller

    Entanglement is present if the smallest-symplectic- eigenvalue ν− of the partial-transposed state is smaller than 1. Entanglement is measured in by logarithmic- negativity Ecal = max(0 , log ν−) [28, 29] and becomes larger as ν− gets smaller

    work page

  21. [21]

    Popescu and D

    S. Popescu and D. Rohrlich, Thermodynamics and the measure of entanglement, Physical Review A 56, R3319 (1997)

    work page 1997

  22. [22]

    Simon, N

    R. Simon, N. Mukunda, and B. Dutta, Quantum-noise matrix for multimode systems: U(n) invariance, squeez- ing, and normal forms, Phys. Rev. A 49, 1567 (1994)

    work page 1994

  23. [23]

    Serafini, F

    A. Serafini, F. Illuminati, and S. De Siena, Symplectic invariants, entropic measures and correlations of gaus- sian states, Journal of Physics B: Atomic, Molecular and Optical Physics 37, L21 (2004)

    work page 2004

  24. [24]

    Giedke and J

    G. Giedke and J. I. Cirac, Characterization of gaussian operations and distillation of gaussian states, Physical Review A 66, 032316 (2002)

    work page 2002

  25. [25]

    Fiur´ aˇ sek and L

    J. Fiur´ aˇ sek and L. Miˇ sta Jr, Gaussian localizable entan- glement, Physical Review A 75, 060302 (2007)

    work page 2007

  26. [26]

    Eisert, S

    J. Eisert, S. Scheel, and M. B. Plenio, Distilling gaussian states with gaussian operations is impossible, Physical Review Letters 89, 137903 (2002)

    work page 2002

  27. [27]

    Gaussian noise can be provided through beam splitter coupling and squeezing can be carried out with JPA operating at low temperatures

    We also note that the idler and signal do not need to be in a thermal state initially, i.e., before the squeezing process r. Gaussian noise can be provided through beam splitter coupling and squeezing can be carried out with JPA operating at low temperatures

    work page

  28. [28]

    N. Wang, S. Du, W. Liu, X. Wang, Y. Li, and K. Peng, Long-distance continuous-variable quantum key distribu- tion with entangled states, Physical Review Applied 10, 064028 (2018)

    work page 2018

  29. [29]

    Vidal and R

    G. Vidal and R. F. Werner, Computable measure of en- tanglement, Phys. Rev. A 65, 032314 (2002)

    work page 2002

  30. [30]

    M. B. Plenio, Logarithmic negativity: A full entangle- ment monotone that is not convex, Phys. Rev. Lett. 95, 090503 (2005)

    work page 2005