pith. sign in

arxiv: 2501.07354 · v2 · submitted 2025-01-13 · 🪐 quant-ph

Enhancing the sensitivity of single microwave photon detection with bandwidth tunability

Louis Pallegoix , Jaime Travesedo , Alexandre S. May , L\'eo Balembois , Denis Vion , Patrice Bertet , Emmanuel Flurin This is my paper

Pith reviewed 2026-05-23 05:49 UTC · model grok-4.3

classification 🪐 quant-ph
keywords microwave photon detectiontransmon qubitbandwidth tuningsingle photon counterquantum sensingsuperconducting devicesspin fluorescence
0
0 comments X

The pith

A bandwidth tunable transmon qubit device reaches 3 × 10^{-23} W/√Hz microwave photon sensitivity.

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

The paper reports a microwave photon counter based on a superconducting transmon qubit that includes a bandwidth tuning circuit. This circuit allows optimization of efficiency and noise performance. With this feature and better device fabrication, the power sensitivity improves to 3 · 10^{-23} W/√Hz. The result is validated by detecting microwave fluorescence from single spins.

Core claim

Incorporating a bandwidth tuning circuit into the transmon qubit photon counter, along with fabrication improvements, yields a power sensitivity of 3 · 10^{-23} W/√Hz. This performance is confirmed by measuring single spin microwave fluorescence.

What carries the argument

The bandwidth tuning circuit which optimizes the device efficiency and noise.

If this is right

  • The enhanced sensitivity supports more precise measurements of weak microwave signals in quantum systems.
  • Single spin fluorescence detection demonstrates the device's utility for quantum sensing applications.
  • The tunable bandwidth enables adaptation to various signal frequencies without hardware changes.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The tuning circuit could be applied to other types of superconducting detectors to boost their sensitivity.
  • Such high sensitivity might open paths to detecting even fainter signals in quantum optics or particle physics experiments.

Load-bearing premise

The bandwidth tuning circuit optimizes efficiency and noise without introducing unaccounted systematic effects or additional noise sources.

What would settle it

Direct measurement of the device's noise spectrum with the tuning circuit active showing excess noise that prevents reaching the claimed sensitivity, or inability to detect the single spin fluorescence at the expected rate.

Figures

Figures reproduced from arXiv: 2501.07354 by Alexandre S. May, Denis Vion, Emmanuel Flurin, Jaime Travesedo, L\'eo Balembois, Louis Pallegoix, Patrice Bertet.

Figure 1
Figure 1. Figure 1: Overview of the device. a) Global layout of the [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Tunability curves. a) Full blue circules are [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: a) Qubit readout histograms after 95650 se [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: a) Four-wave mixing pattern : this color plot shows the measured qubit excited state as a function of [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Measured αth (blue full circles) and αq (orange full circles) as a function of the cryostat’s temperature T, for a detection bandwidth κd/2π = 170 kHz. The solid green line is a fit of αth to αth,0 + Kthn¯th,b(T), yielding αth,0 = 31s−1 and Kth = 2 · 105 s −1 . The solid brown line is a fit of αq to αq,0 + Kqpth,q(T), yielding αq,0 = 7s−1 and Kq = 2.2 · 104 s −1 . The dashed lines are the separated Bose-Ei… view at source ↗
Figure 6
Figure 6. Figure 6: Blue full circles are the measured total dark [PITH_FULL_IMAGE:figures/full_fig_p007_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: It is well fitted by an exponential decay with time constant Γ−1 R = 1.24 ms on top of a constant background, due to the SMPD dark counts. From the integral below the fluorescence curve, we obtain η = 0.4. This implies that the microwave power absorption in-between the spin device and the SMPD is ηloss = 0.85, a very plausible value given that the line includes a superconducting cable, a circulator, and an… view at source ↗
read the original abstract

We report on the characteristics of a microwave photon counter device based on a superconducting transmon qubit. Its design is similar to [arXiv:2307.03614], with an additional bandwidth tuning circuit that allows optimizing the device efficiency and noise. Owing to this new feature and to improvements in device fabrication, a power sensitivity of $3 \cdot 10^{-23} \mathrm{W}/\sqrt{\mathrm{Hz}}$ is reached. We confirm the high performance of the device by measuring single spin microwave fluorescence.

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

2 major / 2 minor

Summary. The manuscript describes a microwave photon counter based on a superconducting transmon qubit, similar to prior work but with an added bandwidth tuning circuit to optimize efficiency and noise. Owing to this circuit and fabrication improvements, it reports a power sensitivity of 3 · 10^{-23} W/√Hz and confirms device performance via measurement of single spin microwave fluorescence.

Significance. If the sensitivity figure is supported by rigorous calibration and the fluorescence measurement serves as independent validation without unaccounted systematics, the result would represent a meaningful advance in single-microwave-photon detection, enabling improved quantum sensing and spin-fluorescence applications. The tunable-bandwidth feature is a constructive design element that addresses a practical limitation in prior devices.

major comments (2)
  1. [Results / Experimental Methods] The central sensitivity claim of 3 · 10^{-23} W/√Hz requires explicit documentation of the calibration procedure, noise-floor determination, integration time, and error bars (including any data-exclusion criteria), as these directly support the reported value and are load-bearing for the abstract's primary result.
  2. [Confirmation Experiment] The confirmation experiment measuring single-spin microwave fluorescence must include quantitative details on how the observed signal-to-noise ratio maps back to the claimed power sensitivity, including any modeling of collection efficiency or background subtraction, to establish that the fluorescence measurement independently validates the sensitivity figure.
minor comments (2)
  1. [Figures] Figure captions and axis labels should explicitly state units, integration bandwidth, and any averaging applied to the sensitivity data for clarity.
  2. [Introduction] A brief comparison table or paragraph quantifying the improvement over the referenced prior device (arXiv:2307.03614) would help contextualize the contribution of the bandwidth-tuning circuit.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their thoughtful review and constructive suggestions. We address each major comment below and will revise the manuscript to incorporate the requested details, thereby strengthening the documentation of our sensitivity claim and validation experiment.

read point-by-point responses

  1. Referee: [Results / Experimental Methods] The central sensitivity claim of 3 · 10^{-23} W/√Hz requires explicit documentation of the calibration procedure, noise-floor determination, integration time, and error bars (including any data-exclusion criteria), as these directly support the reported value and are load-bearing for the abstract's primary result.

    Authors: We agree that the calibration details should be presented more explicitly. In the revised manuscript we will add a new subsection (likely in Methods or Results) that documents the full calibration chain: the procedure used to convert raw counts to incident power, the method for determining the noise floor (including integration time and bandwidth), the calculation of error bars, and any data-exclusion criteria applied. These additions will be supported by references to the relevant figures and, if needed, expanded supplementary material. revision: yes

  2. Referee: [Confirmation Experiment] The confirmation experiment measuring single-spin microwave fluorescence must include quantitative details on how the observed signal-to-noise ratio maps back to the claimed power sensitivity, including any modeling of collection efficiency or background subtraction, to establish that the fluorescence measurement independently validates the sensitivity figure.

    Authors: We will expand the description of the single-spin fluorescence measurement to provide the requested quantitative mapping. The revised text will include: (i) the observed SNR and how it is converted to an equivalent incident power using the calibrated device responsivity, (ii) the model and measured values for collection efficiency, and (iii) the background-subtraction procedure together with its uncertainty. This will make explicit the independent validation of the 3 × 10^{-23} W/√Hz figure. revision: yes

Circularity Check

0 steps flagged

No circularity: experimental measurement report with direct sensitivity figure

full rationale

The paper is an experimental device characterization report. It states a measured power sensitivity of 3·10^{-23} W/√Hz reached via fabrication improvements and a bandwidth-tuning circuit, then confirms performance by direct measurement of single-spin microwave fluorescence. No derivation chain, fitted parameters renamed as predictions, self-citation load-bearing premises, or ansatz smuggling is present in the provided abstract or description. The central claim is a measured quantity validated against an independent experimental benchmark (spin fluorescence), making the result self-contained against external data rather than reducing to its own inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is an experimental device characterization paper; the central claim rests on measured performance rather than theoretical derivations, free parameters, or invented entities.

pith-pipeline@v0.9.0 · 5627 in / 1066 out tokens · 28155 ms · 2026-05-23T05:49:01.959486+00:00 · methodology

discussion (0)

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

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Forward citations

Cited by 2 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Precision hyperfine spectroscopy of an individual nuclear-spin-9/2

    quant-ph 2026-05 unverdicted novelty 7.0

    An Er3+ spin sensor in CaWO4 measures the hyperfine NMR spectrum of a single 93Nb nuclear spin-9/2 with Hertz resolution, determining its site, position, quadrupolar tensor, and two new terms in the spin Hamiltonian.

  2. Analytical performance evaluation of quantum radar architectures: From single-photon to entangled-noise radars

    quant-ph 2026-06 unverdicted novelty 4.0

    Analytical expressions for detection range of quantum direct-detection and entangled-noise radars are derived, with entangled versions treated as enhanced direct-detection systems and a range enhancement factor define...

Reference graph

Works this paper leans on

40 extracted references · 40 canonical work pages · cited by 2 Pith papers · 2 internal anchors

  1. [1]

    Balembois, J

    L. Balembois, J. Travesedo, L. Pallegoix, A. May, E. Bil- laud, M. Villiers, D. Est` eve, D. Vion, P. Bertet, and E. Flurin, Cyclically operated microwave single-photon counter with sensitivity of10−22 W/ √ hz, Phys. Rev. Appl. 21, 014043 (2024)

    work page 2024

  2. [2]

    Orrit and J

    M. Orrit and J. Bernard, Single pentacene molecules detected by fluorescence excitation in a p-terphenyl crys- tal, Physical Review Letters 65, 2716 (1990), publisher: American Physical Society

    work page 1990

  3. [3]

    T. A. Klar, S. Jakobs, M. Dyba, A. Egner, and S. W. Hell, Fluorescence microscopy with diffraction resolution barrier broken by stimulated emission, Proceedings of the National Academy of Sciences of the United States of America 97, 8206 (2000)

    work page 2000

  4. [4]

    Betzig, G

    E. Betzig, G. H. Patterson, R. Sougrat, O. W. Lind- wasser, S. Olenych, J. S. Bonifacino, M. W. Davidson, J. Lippincott-Schwartz, and H. F. Hess, Imaging intracel- lular fluorescent proteins at nanometer resolution, Science (New York, N.Y.) 313, 1642 (2006)

    work page 2006

  5. [5]

    Bruschini, H

    C. Bruschini, H. Homulle, I. M. Antolovic, S. Burri, and E. Charbon, Single-photon avalanche diode imagers in biophotonics: review and outlook, Light, Science & Applications 8, 87 (2019)

    work page 2019

  6. [6]

    Quan- tum cryptography,

    N. Gisin, G. Ribordy, W. Tittel, and H. Zbinden, Quantum cryptography, Review of Modern Physics 74, https://doi.org/10.1103/RevModPhys.74.145 (2002), pub- lisher : American Physical Society

    work page doi:10.1103/revmodphys.74.145 2002

  7. [7]

    Albertinale, L

    E. Albertinale, L. Balembois, E. Billaud, V. Ranjan, D. Flanigan, T. Schenkel, D. Est` eve, D. Vion, P. Bertet, and E. Flurin, Detecting spins by their fluorescence with a microwave photon counter, Nature 600, 434 (2021), publisher: Nature Publishing Group

    work page 2021

  8. [8]

    Z. Wang, L. Balembois, M. Ranˇ ci´ c, E. Billaud, M. Le Dan- tec, A. Ferrier, P. Goldner, S. Bertaina, T. Chaneli` ere, D. Esteve, D. Vion, P. Bertet, and E. Flurin, Single- electron spin resonance detection by microwave photon counting, Nature 619, 276 (2023), number: 7969 Pub- lisher: Nature Publishing Group

    work page 2023

  9. [9]

    Billaud, L

    E. Billaud, L. Balembois, M. L. Dantec, M. Ranˇ ci´ c, E. Albertinale, S. Bertaina, T. Chaneli` ere, P. Goldner, D. Est` eve, D. Vion, P. Bertet, and E. Flurin, Microwave fluorescence detection of spin echoes, Physical Review Letters https://doi.org/10.1103/PhysRevLett.131.100804 (2023)

    work page doi:10.1103/physrevlett.131.100804 2023

  10. [10]

    S. K. Lamoreaux, K. A. van Bibber, K. W. Lehnert, and G. Carosi, Analysis of single-photon and linear ampli- fier detectors for microwave cavity dark matter axion searches, Physical Review D 88, 035020 (2013), publisher: American Physical Society

    work page 2013

  11. [11]

    A. V. Dixit, S. Chakram, K. He, A. Agrawal, R. K. Naik, D. I. Schuster, and A. Chou, Searching for Dark Matter with a Superconducting Qubit, Physical Review Letters 126, 141302 (2021), publisher: American Physical Society

    work page 2021

  12. [12]

    Scigliuzzo, A

    M. Scigliuzzo, A. Bengtsson, J.-C. Besse, A. Wallraff, P. Delsing, and S. Gasparinetti, Primary Thermometry of Propagating Microwaves in the Quantum Regime, Phys- ical Review X 10, 041054 (2020), publisher: American Physical Society

    work page 2020

  13. [13]

    Assouly, R

    R. Assouly, R. Dassonneville, T. Peronnin, A. Bienfait, and B. Huard, Quantum advantage in microwave quantum radar, Nature Physics 19, 1418 (2023), publisher: Nature Publishing Group

    work page 2023

  14. [14]

    Raussendorf, D

    R. Raussendorf, D. E. Browne, and H. J. Briegel, Measurement-based quantum computation on cluster states, Physical Review A 68, 022312 (2003), publisher: American Physical Society

    work page 2003

  15. [15]

    H. J. Briegel, D. E. Browne, W. D¨ ur, R. Raussendorf, and M. Van den Nest, Measurement-based quantum com- putation, Nature Physics 5, 19 (2009), publisher: Nature Publishing Group

    work page 2009

  16. [16]

    Bartolucci, P

    S. Bartolucci, P. Birchall, H. Bombin, H. Cable, C. Daw- son, M. Gimeno-Segovia, E. Johnston, K. Kieling, N. Nick- erson, M. Pant, F. Pastawski, T. Rudolph, and C. Sparrow, Fusion-based quantum computation (2021)

    work page 2021

  17. [17]

    Narla, S

    A. Narla, S. Shankar, M. Hatridge, Z. Leghtas, K. Sliwa, E. Zalys-Geller, S. Mundhada, W. Pfaff, L. Frunzio, R. Schoelkopf, and M. Devoret, Robust Concurrent Remote Entanglement Between Two Superconducting Qubits, Physical Review X 6, 031036 (2016), publisher: American Physical Society

    work page 2016

  18. [18]

    Opremcak, I

    A. Opremcak, I. V. Pechenezhskiy, C. Howington, B. G. Christensen, M. A. Beck, E. Leonard, J. Suttle, C. Wilen, K. N. Nesterov, G. J. Ribeill, T. Thorbeck, F. Schlenker, M. G. Vavilov, B. L. T. Plourde, and R. McDermott, Mea- surement of a superconducting qubit with a microwave photon counter, Science 361, 1239 (2018)

    work page 2018

  19. [19]

    Besse, S

    J.-C. Besse, S. Gasparinetti, M. C. Collodo, T. Walter, A. Remm, J. Krause, C. Eichler, and A. Wallraff, Par- ity detection of propagating microwave fields, Physical Review X (2020)

    work page 2020

  20. [20]

    Lescanne, S

    R. Lescanne, S. Del´ eglise, E. Albertinale, U. R´ eglade, T. Capelle, E. Ivanov, T. Jacqmin, Z. Leghtas, and E. Flurin, Irreversible Qubit-Photon Coupling for the Detection of Itinerant Microwave Photons, Physical Re- view X 10, 021038 (2020)

    work page 2020

  21. [21]

    Romero, J

    G. Romero, J. J. Garc´ ıa-Ripoll, and E. Solano, Microwave Photon Detector in Circuit QED, Physical Review Letters 102, 173602 (2009), publisher: American Physical Society

    work page 2009

  22. [22]

    Helmer, M

    F. Helmer, M. Mariantoni, E. Solano, and F. Marquardt, Quantum nondemolition photon detection in circuit QED and the quantum Zeno effect, Physical Review A 79, 052115 (2009), publisher: American Physical Society

    work page 2009

  23. [23]

    S. R. Sathyamoorthy, L. Tornberg, A. F. Kockum, B. Q. Baragiola, J. Combes, C. Wilson, T. M. Stace, and G. Johansson, Quantum Nondemolition Detection of a Propagating Microwave Photon, Physical Review Letters 112, 093601 (2014), publisher: American Physical Society

    work page 2014

  24. [24]

    Kyriienko and A

    O. Kyriienko and A. S. Sørensen, Continuous-Wave Single- Photon Transistor Based on a Superconducting Circuit, Physical Review Letters 117, 140503 (2016), publisher: American Physical Society

    work page 2016

  25. [25]

    S. R. Sathyamoorthy, T. M. Stace, and G. Johansson, Detecting itinerant single microwave photons, Comptes Rendus. Physique 17, 756 (2016)

    work page 2016

  26. [26]

    X. Gu, A. F. Kockum, A. Miranowicz, Y.-x. Liu, and F. Nori, Microwave photonics with superconducting quan- tum circuits, Physics Reports Microwave photonics with superconducting quantum circuits, 718-719, 1 (2017)

    work page 2017

  27. [27]

    Royer, A

    B. Royer, A. L. Grimsmo, A. Choquette-Poitevin, and A. Blais, Itinerant Microwave Photon Detector, Physical Review Letters 120, 203602 (2018), publisher: American Physical Society. 12

    work page 2018

  28. [28]

    Y.-F. Chen, D. Hover, S. Sendelbach, L. Maurer, S. T. Merkel, E. J. Pritchett, F. K. Wilhelm, and R. McDermott, Microwave photon counter based on josephson junctions, Physical Review Letters 10.1103/PhysRevLett.107.217401 (2011)

    work page doi:10.1103/physrevlett.107.217401 2011

  29. [29]

    Koshino, K

    K. Koshino, K. Inomata, T. Yamamoto, and Y. Naka- mura, Implementation of an impedance-matched λ sys- tem by dressed-state engineering, Physical Review Letter 10.1103/PhysRevLett.111.153601 (2013)

    work page doi:10.1103/physrevlett.111.153601 2013

  30. [30]

    Single microwave-photon detector using an artificial $\Lambda$-type three-level system

    K. Inomata, Z. Lin, K. Koshino, W. D. Oliver, J.-S. Tsai, T. Yamamoto, and Y. Nakamura, Single microwave- photon detector using an artificial $\Lambda$-type three- level system, Nature Communications 7, 12303 (2016), arXiv:1601.05513 [cond-mat, physics:quant-ph]

    work page internal anchor Pith review Pith/arXiv arXiv 2016

  31. [31]

    Besse, S

    J.-C. Besse, S. Gasparinetti, M. C. Collodo, T. Wal- ter, P. Kurpiers, M. Pechal, C. Eichler, and A. Wallraff, Single-Shot Quantum Nondemolition Detection of Indi- vidual Itinerant Microwave Photons, Physical Review X 8, 021003 (2018), publisher: American Physical Society

    work page 2018

  32. [32]

    S. Kono, K. Koshino, Y. Tabuchi, A. Noguchi, and Y. Nakamura, Quantum non-demolition detection of an itinerant microwave photon, Nature Physics 14, 546 (2018), arXiv:1711.05479 [quant-ph]

    work page internal anchor Pith review Pith/arXiv arXiv 2018

  33. [33]

    C. H. Wong and M. G. Vavilov, Quantum efficiency of a single microwave photon detector based on a semiconduc- tor double quantum dot, Physical Review A 10.1103/Phys- RevA.95.012325 (2017)

    work page doi:10.1103/phys- 2017

  34. [34]

    Ghirri, S

    A. Ghirri, S. Cornia, and M. Affronte, Microwave photon detectors based on semiconducting double quantum dots, Sensors https://doi.org/10.3390/s20144010 (2020)

    work page doi:10.3390/s20144010 2020

  35. [35]

    G.-H. Lee, D. K. Efetov, W. Jung, L. Ranzani, E. D. Walsh, T. A. Ohki, T. Taniguchi, K. Watanabe, P. Kim, D. Englund, and K. C. Fong, Graphene-based Josephson junction microwave bolometer, Nature 586, 42 (2020), number: 7827 Publisher: Nature Publishing Group

    work page 2020

  36. [36]

    Quantum-Enhanced Sensing of Axion Dark Matter with a Transmon-Based Single Microwave Photon Counter

    C. Braggio, L. Balembois, R. Di Vora, Z. Wang, J. Trav- esedo, L. Pallegoix, G. Carugno, A. Ortolan, G. Ruoso, U. Gambardella, D. D’Agostino, P. Bertet, and E. Flurin, Quantum-enhanced sensing of axion dark matter with a transmon-based single microwave photon counter (2024), arXiv:2403.02321 [hep-ex, physics:quant-ph]

    work page arXiv 2024

  37. [37]

    Blais, A

    A. Blais, A. L. Grimsmo, S. Girvin, and A. Wallraff, Circuit quantum electrodynamics, Reviews of Modern Physics (2021)

    work page 2021

  38. [38]

    Travesedo, J

    J. Travesedo, J. O’Sullivan, L. Pallegoix, Z. W. Huang, P. Hogan, P. Goldner, T. Chaneliere, S. Bertaina, D. Es- teve, P. Abgrall, D. Vion, E. Flurin, and P. Bertet, All- microwave readout, spectroscopy, and dynamic polar- ization of individual nuclear spins in a crystal (2024), arXiv:2408.14282 [cond-mat, physics:quant-ph]

    work page arXiv 2024

  39. [39]

    O’Sullivan, J

    J. O’Sullivan, J. Travesedo, L. Pallegoix, Z. Huang, P. Hogan, P. Goldner, D. Esteve, D. Vion, P. Bertet, and E. Flurin, Individual solid-state nuclear sin qubits with coherence exceeding seconds (2024), coming soon

    work page 2024

  40. [40]

    Albertinale, Measuring spin fluorescence with a mi- crowave photon detector, Ph.D

    E. Albertinale, Measuring spin fluorescence with a mi- crowave photon detector, Ph.D. thesis, Universit´ e Paris- Saclay (2021)

    work page 2021