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REVIEW 3 major objections 5 minor 2 cited by

Characterization of Nanostructural Imperfections in Superconducting Quantum Circuits

T0 review · 3 major / 5 minor · reviewed 2026-08-10 · deepseek-v4-flash

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Pith's one-line read Atomic-scale maps show lossy oxide and carbon layers sit at air-exposed interfaces, not the buried metal-substrate boundary.

desk verdict A careful STEM/EDS/EELS look at qubit interfaces that overreaches in the abstract; the observations themselves are believable and worth having. read the letter →

arxiv 2501.15059 v3 pith:AUZPASU5 submitted 2025-01-25 quant-ph physics.app-ph

Mohammed Alghadeer , Simone D Fasciati , Shuxiang Cao , Michele Piscitelli , Matthew C. Spink , David G. Hopkinson , Mohsen Danaie , Susannah C. Speller
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Peter J. Leek Mustafa Bakr
This is my paper · ORCID
classification quant-phphysics.app-ph
keywords superconductingqubitstwo-levelsystemsTLSdefectsinterfaceoxidationcarboncontaminationscanningtransmissionelectronmicroscopyenergylossspectroscopydielectric
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

This paper uses atomic-resolution cross-sectional imaging to ask where dielectric loss in a superconducting transmon device physically lives. By cutting thin lamellae through a Josephson junction and a spiral resonator and mapping elements with scanning transmission electron microscopy plus X-ray and electron-energy-loss spectroscopy, the authors find 7–20 nm aluminum-oxide layers and carbon contamination at the metal-air and substrate-air interfaces, while the buried metal-substrate interface is relatively clean. They interpret these air-exposed imperfections as the microstructural sources of two-level-system loss that limit qubit coherence and resonator quality factors. If true, it redirects mitigation effort: protect or clean the exposed surfaces rather than assuming the metal-substrate junction is the problem. The paper is careful to call the findings qualitative trends, since they rest on a limited number of lamellae.

What carries the argument

The load-bearing tool is cross-sectional scanning transmission electron microscopy combined with two spectroscopies: energy-dispersive X-ray spectroscopy (EDS) and electron-energy-loss spectroscopy (EELS). FIB-milled lamellae through the junction and resonator are thinned to electron transparency, and one-nanometer-sliced linescans reconstruct elemental profiles across each interface, distinguishing oxygen, aluminum, silicon, carbon, and platinum. The O K-edge EELS analysis, with background removed by power-law fitting and cross sections computed from generalized oscillator strengths, lets the authors identify aluminum oxide layers and carbon contamination at specific interfaces rather than inferring them indirectly from microwave loss.

What would settle it

Compare these maps with a lamella prepared without ion milling or platinum capping—for example by cryo-fracture or broad-beam polishing—and check whether the 7–20 nm oxide and carbon layers at the air interfaces remain; if they disappear, they were preparation artifacts. Alternatively, on identical devices, strip exactly these surface layers with a short wet etch or in-situ plasma clean and measure resonator internal quality factors: if the quality factor does not move, those layers are not the limiting loss.

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Extended reading notes

Core claim

The central discovery is that the critical interfaces are not equally bad. Oxygen and carbon maps from two lamellae, one through the Josephson junction and one through the spiral inductor, show pronounced oxide formation at the metal-air and substrate-air surfaces, with thicknesses around 7–20 nm and higher carbon concentration at the base and sidewalls of the etched aluminum film, while the metal-substrate boundary shows no relative oxygen signal and sharp elemental transitions. The tunnel barrier of the junction, formed by in-situ static oxidation, shows lower carbon contamination than the air-formed oxide layers. The authors connect these observations to the fabrication sequence: wet etching and photolithography preferentially contaminate sidewalls and base, and ambient exposure grows the surface oxide, so the resulting amorphous dielectric layers are plausible hosts for two-level-system defects that dissipate microwave energy. The stated conclusion is that two-level-system imperfections at these air-exposed interfaces significantly contribute to limiting device performance.

Load-bearing premise

The conclusions assume that the two FIB-prepared lamellae fairly represent the device interfaces and that the milling and capping steps did not create or erase the oxide and carbon features; the paper itself notes the findings are qualitative trends from a limited number of lamellae.

Editorial extensions

If this is right

  • If the air-exposed interfaces are the dominant two-level-system host, then cleaning or passivating metal-air and substrate-air surfaces should raise qubit T1 and resonator internal quality factors more than improvements to the buried metal-substrate interface.
  • The 7–20 nm surface-oxide thicknesses set a scale: any protective cap or surface treatment must prevent regrowth of these layers, not just remove them once.
  • Higher carbon at the base and sidewalls of etched aluminum implicates wet-etch and lithography residues as a controllable contamination source, so altering those steps should reduce loss non-uniformity across a wafer.
  • A clean metal-substrate interface in both lamellae means substrate-air loss and metal-air loss, not metal-substrate loss, are where fabrication-process changes can be expected to matter.
  • The low carbon in the in-situ oxidized tunnel barrier supports keeping the junction oxidation step in vacuum or controlled gas, since that interface appears comparatively pure.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A testable prediction follows: if these air-interface layers are the loss source, then removing them with a gentle surface clean or capping them before ambient exposure should produce a measurable rise in resonator internal quality factor on identically fabricated devices.
  • The spatial pattern—thicker oxide at the base and sidewalls than at the top—suggests the wet-etch step, not just ambient oxidation, is a key variable; comparing the same process with dry etching or added plasma ashing would isolate its contribution.
  • Because the conclusions rest on two lamellae, a robust extension would be statistical sampling: prepare several lamellae from different chips and correlate per-lamella oxide and carbon thickness with qubit T1 measured on the same chip, something the current qualitative study explicitly does not attempt.
  • If the metal-substrate interface is genuinely clean, then published improvements that target only that boundary may be less impactful than surface passivation of air-exposed interfaces, an ordering that could be tested by comparing device performance under the two treatment families.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. This paper reports atomic-scale structural and chemical characterization of cross-sectional lamellae extracted from a Josephson junction (qubit side) and a spiral inductor (resonator side) of a double-sided superconducting circuit fabricated on intrinsic silicon. Using STEM with EDS and EELS, the authors identify oxide layers approximately 7-20 nm thick and carbon contamination at the metal-air and substrate-air interfaces, while the buried metal-substrate interface appears relatively clean. They attribute these features to the patterning, wet-etching, resist-removal, and ambient-exposure steps of their fabrication process. The paper also reports basic microwave characterization of 16 qubits and 16 resonators from the same wafer (mean T1 = 71 +/- 5 microseconds, mean Qi about 10^4) and argues that the observed interface disorder suggests that TLS imperfections at critical interfaces significantly contribute to limiting device performance.

Significance. The study's strength is its direct, atomic-scale evidence about where oxides and carbon reside in a specific Al/Si fabrication flow, with careful vacuum transfer and combined EDS/EELS analysis. If the observations are representative, they support the emerging picture that air-exposed interfaces are the dominant impurity sites and that the buried MS interface is comparatively clean, with concrete implications for process mitigation (e.g., post-etch cleaning, passivation, controlled ambient exposure). The authors are explicit that their results are qualitative and that no direct quantitative correlation with qubit performance is established, which is appropriate. However, because the abstract and conclusion assert a stronger causal role than the evidence supports, the paper's significance is as a materials case study rather than as a loss-budget or TLS-mechanism demonstration.

major comments (3)
  1. [Abstract; Microwave Characterization] The abstract and conclusion claim that TLS imperfections at critical interfaces 'significantly contribute to limiting device performance,' but the microwave section explicitly states that 'a direct quantitative correlation between atomic-scale material imperfections and individual qubit performance is not established here.' The device-level data in Table 2 (mean T1 = 71 +/- 5 microseconds; mean internal quality factor Qi about 10.1 x 10^4) are compatible with many loss channels; no power-dependent TLS spectroscopy, no comparison with control samples, and no loss-budget estimate based on the observed 7-20 nm oxide/carbon layers are presented. This is a load-bearing gap because it is the step from 'dirty interfaces are present' to 'dirty interfaces limit this device's coherence.' Please soften the abstract and conclusion to 'potential sources' or 'plausible contributors,' or add a quantitative link (e.g., estimated TLS loss tangent from the observed layer volumes) that supports the stronger claim.
  2. [Results and Discussion (first paragraph); Materials Characterization (FIB-SEM)] The authors correctly state that their findings 'represent qualitative trends observed across a limited number of cross-sectional lamellae' and that quantitative analysis 'would not be robust and reproducible.' Yet the central qualitative conclusion about the relative cleanliness of MA, SA, and MS interfaces is based on an unreported number of lamellae; from the described methods it appears that one lamella was prepared from each of the two components. The manuscript does not state how many lamellae were examined, how many regions were analyzed on each, or whether the observed contrasts were reproduced at other locations. Please add this sampling information or explicitly restrict the claims to the examined cross-sections; as written, the reader cannot assess the representativeness on which the general conclusion depends.
  3. [Materials Characterization (Sample Preparation using FIB-SEM); Results and Discussion (Figs. 4-8)] The FIB workflow uses Ga+ ion milling and Pt deposition from an organometallic precursor. The authors note that carbon in the Pt capping layer originates from the GIS precursor, but no assessment is provided of whether FIB-induced damage, redeposition, or electron/ion-beam-induced chemistry could create or enhance the oxide and carbon signals at the MA and SA interfaces. Because the paper quotes oxide thicknesses to the nanometer level (e.g., 'approximately 10 nm thick' for Line-1 in Fig. 4 and 'approximately 20 nm thick' for Line-1 in Fig. 8), please include a control discussion or literature evidence that the observed layers are not preparation artifacts, or reduce the level of quantitative specificity in these claims.
minor comments (5)
  1. [Results and Discussion, first paragraph] 'For this reasons' should be 'For this reason.'
  2. [Introduction; Conclusion; Microwave Characterization] Please correct 'emphasizes on the need' and 'emphasize on the fact' to 'emphasizes the need' and 'emphasize the fact,' and 'receptively' to 'respectively.'
  3. [Fig. 2] The text refers to 'Fig. 2(c)' and 'Fig. 2(d)' for the final thinned lamellae, but the caption lists only panels (a) and (b); please align the references and the figure panels.
  4. [Microwave Characterization] 'Qubits relaxation and coherence times' should be 'Qubit relaxation and coherence times,' and 'with weighted-standard deviations' should be 'with weighted standard deviations.'
  5. [Table 2 and caption] The caption describes parameters but does not state which uncertainties are shown; clarify whether Qi has an associated uncertainty or note that only qubit-time uncertainties are listed.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: observational characterization study with no fitted model or derivation that reduces to its inputs.

full rationale

This paper is an observational materials-characterization study. Its central claim is that STEM/EDS/EELS cross-sections reveal oxide layers and carbon contamination at the metal-air and substrate-air interfaces of a Josephson junction and a spiral resonator, and that these imperfections plausibly host TLS defects that limit qubit performance. There is no derivation chain, no fitted parameter that is later renamed as a prediction, and no equation whose output is equivalent to its input by construction. The microwave data are reported separately and the paper explicitly states that 'a direct quantitative correlation between atomic-scale material imperfections and individual qubit performance is not established here,' which undercuts, rather than creates, any circular forcing. The jump from 'dirty interfaces exist' to 'these significantly limit device performance' is a causal-inference gap, but it is not circularity: the observations are not defined in terms of the conclusion, and the conclusion is not an input to the measurement. Self-citations to the authors' prior work (e.g., refs. 34, 35 on surface passivation, and refs. 43, 44 for fabrication details) are used for context and process description, not as load-bearing justification of the main result. The paper is self-contained as a characterization report, with limitations acknowledged in the text ('qualitative trends observed across a limited number of cross-sectional lamellae'). No circular step meeting the specified criteria is present.

Assumptions & free parameters 0 free parameters · 4 assumptions · 0 invented entities

No free parameters are fitted; the paper is purely observational. The main unstated premises are the representativeness of the lamellae, the absence of FIB-induced artifacts, and the accuracy of the EELS/EDS quantification model.

assumptions (4)
  • domain assumption EELS/EDS background subtraction and cross-section fitting yield accurate relative elemental distributions in the lamellae.
    The paper removes a power-law background before the O K-edge and fits edges with generalized oscillator strengths (Methodology, Materials Characterization). Accuracy of relative concentrations depends on these model assumptions.
  • domain assumption FIB lamella preparation and vacuum transfer do not significantly alter the native oxide or carbon distributions being measured.
    The authors use Pt capping and vacuum transfer to minimize artifacts, but ion milling can still cause amorphization, redeposition, and local compositional changes (Materials Characterization).
  • domain assumption The limited number of cross-sectional lamellae is representative of device-wide interface conditions.
    Stated in Results and Discussion: 'qualitative trends observed across a limited number of cross-sectional lamellae.' The whole paper's generalization rests on this.
  • domain assumption The carbon signal within the Pt capping layer originates from the GIS precursor, not from device contamination, and the Si signal in Pt is a projection artifact.
    The paper asserts these interpretations (Fig. 3 caption, Fig. 5 note) to distinguish real device features from preparation artifacts.

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Cite this review

Pith. "Pith review of Characterization of Nanostructural Imperfections in Superconducting Quantum Circuits." pith.science (2026). https://pith.science/paper/AUZPASU5

@misc{pith2026250115059,
  author       = {Pith},
  title        = {Pith review of: Characterization of Nanostructural Imperfections in Superconducting Quantum Circuits},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/AUZPASU5}},
  note         = {Machine review of arXiv:2501.15059}
}
read the original abstract

Decoherence in superconducting quantum circuits, caused by loss mechanisms like material imperfections and two-level system (TLS) defects, remains a major obstacle to improving the performance of quantum devices. In this work, we present atomic-level characterization of cross-sections of a Josephson junction and a spiral resonator to assess the quality of critical interfaces. Employing scanning transmission electron microscopy (STEM) combined with energy-dispersive X-ray spectroscopy (EDS) and electron-energy loss spectroscopy (EELS), we identify structural imperfections associated with oxide layer formation and carbon-based contamination, and correlate these imperfections to the patterning and etching steps in the fabrication process and environmental exposure. These results suggest that TLS imperfections at critical interfaces significantly contribute to limiting device performance, emphasizing the need for an improved fabrication process.

Figures

Figures reproduced from arXiv: 2501.15059 by the authors.

Figure 1
Figure 1. (a) Optical image of the qubit indicating the location where the lamella was extracted for scanning transmission electron microscopy (STEM) analysis. (b) Optical image of the resonator showing the lamella extraction site. 2/13 [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. (c) and [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. (a) Scanning electron microscopy (SEM) images showing the location from which the lamella was extracted from the qubit side for cross-sectional analysis of the Josephson junction. (b) Cross-sectional STEM combined with dispersive X-ray spectroscopy (EDS) elemental maps of both sides of the lamella from the Josephson junction area, highlighting the elemental compositions of oxygen (red), aluminum (green), silicon (bl… view at source ↗
Figures from the paper (5 more)
Figure 4
Figure 4. Figure 4: (a) and (d)), we observe that the AlOx layer within the junction (ROI-2) appears to have the lowest amount of carbon contamination compared to the oxygen-rich layers at the top and side surfaces, suggesting a higher purity in the tunnel barrier. However, in the left se…
Figure 5
Figure 5. Figure 5: (a) Scanning transmission electron microscopy (STEM) combined with electron-energy loss spectroscopy (EELS) maps of the middle section of the lamella extracted from the spiral inductor, with regions of interest across the interface indicated by boxes.The elemental comp…
Figure 6
Figure 6. Figure 6: (a) Cross-sectional scanning transmission electron microscopy (STEM) image of the left side of the lamella extracted from the resonator side showing locations of electron-energy loss spectroscopy (EELS) maps, highlighting the elemental compositions of oxygen (red), alu…
Figure 7
Figure 7. Figure 7: (a) Cross-sectional scanning transmission electron microscopy (STEM) images of the right side of the lamella from the resonator side, highlighting the elemental compositions of oxygen (red), aluminum (green), and silicon (blue). (b) Individual colored images of oxygen,…
Figure 8
Figure 8. Figure 8: (a) Cross-sectional scanning transmission electron microscopy (STEM) colored images at right of the lamella at the location of a structural imperfection from the resonator side, highlighting the elemental compositions of oxygen (red), aluminum (green), and silicon (blu…

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Forward citations

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Works this paper leans on

47 extracted references · 42 canonical work pages · cited by 2 Pith papers

  1. [1]

    Brecht, T. et al. Demonstration of superconducting micromachined cavities. Appl. Phys. Lett. 107 (2015)

    work page 2015

  2. [2]

    Place, A. P. et al. New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds. Nat. communications 12, 1779 (2021)

    work page 2021

  3. [3]

    Vepsäläinen, A. et al. Improving qubit coherence using closed-loop feedback. Nat. Commun. 13, 1932 (2022)

    work page 2022

  4. [4]

    Somoroff, A. et al. Millisecond coherence in a superconducting qubit. Phys. Rev. Lett. 130, 267001 (2023)

    2023

  5. [5]

    Ganjam, S. et al. Surpassing millisecond coherence in on chip superconducting quantum memories by optimizing materials and circuit design. Nat. Commun. 15, 3687 (2024)

    work page 2024

  6. [6]

    Milul, O. et al. Superconducting cavity qubit with tens of milliseconds single-photon coherence time. PRX Quantum 4, 030336 (2023)

    work page 2023

  7. [7]

    Mohseni, M. et al. How to build a quantum supercomputer: Scaling challenges and opportunities. arXiv preprint arXiv:2411.10406 (2024)

    arXiv 2024

  8. [8]

    Zanuz, D. C. et al. Mitigating losses of superconducting qubits strongly coupled to defect modes. arXiv preprint arXiv:2407.18746 (2024)

    arXiv 2024

Show all 47 references
  1. [9]

    V .et al

    Abdurakhimov, L. V .et al. Identification of different types of high-frequency defects in superconducting qubits. PRX Quantum 3, 040332 (2022)

    2022

  2. [10]

    Bilmes, A. et al. Resolving the positions of defects in superconducting quantum bits. Sci. reports 10, 3090 (2020)

    2020

  3. [11]

    Houck, A. et al. Controlling the spontaneous emission of a superconducting transmon qubit. Phys. review letters 101, 080502 (2008)

    2008

  4. [13]

    J., Devoret, M

    Catelani, G., Schoelkopf, R. J., Devoret, M. H. & Glazman, L. I. Relaxation and frequency shifts induced by quasiparticles in superconducting qubits. Phys. Rev. B 84, 064517 (2011)

    2011

  5. [14]

    Martinis, J. M. et al. Decoherence in josephson qubits from dielectric loss. Phys. review letters 95, 210503 (2005)

    2005

  6. [15]

    Müller, C., Cole, J. H. & Lisenfeld, J. Towards understanding two-level-systems in amorphous solids: insights from quantum circuits. Reports on Prog. Phys. 82, 124501 (2019)

    2019

  7. [16]

    Gao, J. et al. Experimental evidence for a surface distribution of two-level systems in superconducting lithographed microwave resonators. Appl. Phys. Lett. 92 (2008)

    2008

  8. [17]

    Determining interface dielectric losses in superconducting coplanar-waveguide resonators

    Woods, W.et al. Determining interface dielectric losses in superconducting coplanar-waveguide resonators. Phys. Rev. Appl. 12, 014012 (2019)

    2019

  9. [18]

    Wisbey, D. S. et al. Effect of metal/substrate interfaces on radio-frequency loss in superconducting coplanar waveguides. J. Appl. Phys. 108 (2010)

    2010

  10. [19]

    Earnest, C. T.et al. Substrate surface engineering for high-quality silicon/aluminum superconducting resonators.Supercond. Sci. Technol. 31, 125013 (2018)

    2018

  11. [20]

    McRae, C. R. H. et al. Dielectric loss extraction for superconducting microwave resonators. Appl. Phys. Lett. 116 (2020)

    2020

  12. [21]

    Murray, C. E. Material matters in superconducting qubits. Mater. Sci. Eng. R: Reports 146, 100646 (2021)

    2021

  13. [22]

    The physics of superconducting microwave resonators (California Institute of Technology, 2008)

    Gao, J. The physics of superconducting microwave resonators (California Institute of Technology, 2008)

    2008

  14. [23]

    Calusine, G. et al. Analysis and mitigation of interface losses in trenched superconducting coplanar waveguide resonators. Appl. Phys. Lett. 112 (2018). 12/13

    2018

  15. [24]

    Lisenfeld, J. et al. Observation of directly interacting coherent two-level systems in an amorphous material. Nat. communications 6, 6182 (2015)

    2015

  16. [25]

    Richardson, C. J. et al. Fabrication artifacts and parallel loss channels in metamorphic epitaxial aluminum superconducting resonators. Supercond. Sci. Technol. 29, 064003 (2016)

    2016

  17. [26]

    Megrant, A. et al. Planar superconducting resonators with internal quality factors above one million. Appl. Phys. Lett. 100 (2012)

    2012

  18. [27]

    & Olszta, M

    Richardson, C., Alexander, A., Weddle, C., Arey, B. & Olszta, M. Low-loss superconducting titanium nitride grown using plasma-assisted molecular beam epitaxy. J. Appl. Phys. 127 (2020)

    2020

  19. [28]

    Altoé, M. V . P.et al. Localization and mitigation of loss in niobium superconducting circuits. PRX Quantum 3, 020312 (2022)

    2022

  20. [29]

    Ding, Z. et al. A stable and low loss oxide for superconducting qubits. arXiv preprint arXiv:2305.11395 (2023)

    2023 arXiv

  21. [30]

    Zheng, K. et al. Nitrogen plasma passivated niobium resonators for superconducting quantum circuits. Appl. Phys. Lett. 120 (2022)

    2022

  22. [31]

    Bal, M. et al. Systematic improvements in transmon qubit coherence enabled by niobium surface encapsulation. npj Quantum Inf. 10, 43 (2024)

    2024

  23. [32]

    Chang, R. D. et al. Eliminating surface oxides of superconducting circuits with noble metal encapsulation. arXiv preprint arXiv:2408.13051 (2024)

    2024 arXiv

  24. [33]

    Karuppannan, S. K. et al. Improved interface of niobium superconducting resonator with ruthenium as a capping layer. ACS Appl. Electron. Mater. (2024)

    2024

  25. [34]

    Alghadeer, M. et al. Surface passivation of niobium superconducting quantum circuits using self-assembled monolayers. ACS Appl. Mater. & Interfaces 15, 2319–2328 (2022)

    2022

  26. [35]

    Alghadeer, M. et al. Mitigating coherent loss in superconducting circuits using molecular self-assembled monolayers. Sci. Reports 14, 27340 (2024)

    2024

  27. [36]

    Chistolini, T. et al. Performance of superconducting resonators suspended on sin membranes. arXiv preprint arXiv:2405.01784 (2024)

    2024 arXiv

  28. [37]

    Jünger, C. et al. Implementation of scalable suspended superinductors. arXiv preprint arXiv:2411.10396 (2024)

    2024 arXiv

  29. [38]

    Engineering high-coherence superconducting qubits

    Siddiqi, I. Engineering high-coherence superconducting qubits. Nat. Rev. Mater. 6, 875–891 (2021)

    2021

  30. [39]

    Koch, J. et al. Charge-insensitive qubit design derived from the cooper pair box. Phys. Rev. A 76, 042319 (2007)

    2007

  31. [40]

    Rahamim, J. et al. Double-sided coaxial circuit qed with out-of-plane wiring. Appl. Phys. Lett. 110 (2017)

    2017

  32. [41]

    Spring, P. A. et al. High coherence and low cross-talk in a tileable 3d integrated superconducting circuit architecture. Sci. Adv. 8, eabl6698 (2022)

    2022

  33. [42]

    Fasciati, S. D. et al. Complementing the transmon by integrating a geometric shunt inductor. arXiv preprint arXiv:2410.10416 (2024)

    2024 arXiv

  34. [43]

    Experiments on multi-level superconducting qubits and coaxial circuit QED

    Peterer, M. Experiments on multi-level superconducting qubits and coaxial circuit QED . Ph.D. thesis, University of Oxford (2016)

    2016

  35. [44]

    Implementation of variational quantum algorithms on superconducting qudits

    Cao, S. Implementation of variational quantum algorithms on superconducting qudits . Ph.D. thesis, University of Oxford (2023)

    2023

  36. [45]

    & Dunsmuir, J

    Dolan, G. & Dunsmuir, J. Very small ( 20 nm) lithographic wires, dots, rings, and tunnel junctions. Phys. B: Condens. Matter 152, 7–13 (1988)

    1988

  37. [46]

    de la Peña, F. et al. hyperspy/hyperspy: v2.3.0. https://zenodo.org/records/14956374 (2025)

    2025

  38. [47]

    & Kohl, H

    Segger, L., Guzzinati, G. & Kohl, H. Generalised oscillator strengths for the simulation of eels spectra, with a broader coverage of high energy and minor edges. https://zenodo.org/records/7645765 (2023)

    2023

  39. [48]

    Hertzberg, J. B. et al. Laser-annealing josephson junctions for yielding scaled-up superconducting quantum processors. npj Quantum Inf. 7, 129 (2021). 13/13

    2021

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