REVIEW 2 major objections 5 minor 77 references
Quantum Geometric Friedel Oscillations
T0 review · 2 major / 5 minor · reviewed 2026-07-13 · grok-4.5
Pith's one-line read Quantum geometry creates temperature-stable Friedel oscillations whose period tracks quantum-metric hot spots and whose decay is set by the quantum-metric length.
desk verdict Clean derivation of a new geometric channel in flat-band Friedel response whose period and range are fixed by metric hot spots and ℓ_QM; the only soft spot is the already-scoped interband bound. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The decomposition of the flat-band susceptibility into a conventional Lindhard piece plus a geometric piece proportional to the quantum distance d_k,k+q between Bloch states; at high temperature the geometric piece reduces to the averaged quantum distance, whose Fourier transform yields the QGFO spectrum, while the residue poles of the flat-band projector fix the decay length to the quantum-metric length.
What would settle it
In a candidate flat-band metal (for example magic-angle twisted bilayer graphene at low filling), STM maps of impurity-induced density oscillations at temperatures above the flat-band width should show a residual oscillatory period equal to the known quantum-metric hot-spot separation and a temperature-independent envelope whose length matches the independently computed quantum-metric length; absence of that residual signal would falsify the claim.
Extended reading notes
Core claim
In metals with an isolated nearly flat band at the Fermi energy, quantum geometry induces a distinct class of real-space charge oscillations (QGFOs) whose wavevector is set by the separation of quantum-metric hot spots and whose exponential decay length is bounded by the quantum-metric length obtained by integrating the trace of the quantum metric over the Brillouin zone; these oscillations persist for temperatures much larger than the flat-band bandwidth while conventional 2k_F oscillations are thermally suppressed.
Load-bearing premise
The flat-band projection of the susceptibility stays accurate whenever temperature and impurity strength remain much smaller than the gap to neighboring bands, so that interband contributions can be neglected.
Signed reviews
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript argues that conventional Friedel theory is incomplete for metals with an isolated (nearly) flat band at the Fermi energy: nontrivial Bloch geometry produces an additional oscillatory channel, quantum geometric Friedel oscillations (QGFOs). Their period is set by the momentum-space separation of quantum-metric hot spots of the flat band, while their spatial decay is controlled by the quantum metric length ℓ_QM (the Brillouin-zone integral of Tr G_f). At low T the conventional 2k_F and geometric components coexist; for k_B T ≳ W_f (and already for k_B T ∼ E_F^f) the 2k_F channel is thermally suppressed while QGFOs survive, with a temperature-independent decay plateau set by ℓ_QM. The claim is supported by a flat-band projected susceptibility decomposed into conventional and geometric pieces, a high-T reduction χ^f(q) ∝ 1 − D̄^f(q), a residue analysis of the projected Green function, an exact variance identity Ω_QGFOs = 2a ℓ_QM, and numerical spectra for 1D three-band, 1D two-band, and 2D models.
Significance. If correct, the work supplies a concrete, real-space spectroscopic signature of quantum geometry—period fixed by hot-spot separations and decay fixed by the integrated quantum metric—that remains visible when kinetic energy is overwhelmed by temperature. That is a useful addition to the growing toolkit of quantum-geometric responses and is directly relevant to flat-band platforms (magic-angle TBG, layered electrides, etc.). Strengths that should be credited explicitly are: (i) the clean high-T reduction of the susceptibility to the averaged quantum distance; (ii) the residue decomposition that isolates three oscillatory channels; (iii) the model-independent variance proof that Ω_QGFOs = 2a ℓ_QM (and the Chern lower bound in 2D); and (iv) consistent numerical checks across three distinct lattice models, including an intermediate-T window controlled by a partially averaged quantum distance. These elements make the geometric origin of the oscillations falsifiable rather than merely interpretive.
major comments (2)
- The flat-band projection (Eq. 3 and the χ_c^f + χ_g^f split) is the load-bearing step for claiming that QGFOs dominate once conventional oscillations are washed out. SM Note III bounds interband pieces by O(1/Δ_g) in the window W_f ≪ T ≪ Δ_g and shows they are negligible there; the intermediate window k_B T ≃ E_F^f ≪ W_f (Figs. 3 and 6, Eq. 10) is handled only by the partial average D̄_p and by full-band numerics. A short quantitative decomposition of interband vs. flat-band χ(q) at that intermediate temperature—or an explicit statement that the O(1/Δ_g) bound continues to hold when the Fermi window is only partially filled—would close the only soft spot in the central claim.
- End Matter derives the exact second-moment identity Ω_QGFOs = 2a ℓ_QM from the high-T form (A3)–(A6). The main text and SM Note I also speak of an exponential envelope e^{−r/ξ_G} with ξ_G ≥ λ ℓ_QM set by Im(k_nf). For multi-pole or multi-hot-spot spectra the variance and the leading exponential length are related but not identical; a one-paragraph clarification of when the variance bound and the pole-imaginary-part bound coincide (and when the oscillatory multi-component form of Eq. S18 is needed) would prevent over-reading of the “decay length = ℓ_QM” language in the abstract and introduction.
minor comments (5)
- Fig. 1(d) caption and main text refer to a “purely quantum-geometric plateau” set by ℓ_QM; it would help the reader if the numerical value of ℓ_QM for the plotted parameters were stated explicitly next to the plateau, so that the equality with the extracted ξ can be checked by eye.
- Notation for the quantum distance is written both d_{k,k′} and d^f_{k,k+q}; a single consistent superscript convention would reduce friction when comparing Eq. (5), Eq. (10), and the SM.
- In the 2D End Matter discussion, the statement that inversion breaking is “not a generic requirement” for QGFOs is important; a brief cross-reference back to the 1D case (where δ ≠ δ′ is required) would make the symmetry conditions clearer.
- A few typos and typesetting issues: “Friedal” (Introduction), “arXiv:2607.04654v2” date line, and occasional missing spaces around k_B T / W_f inequalities. None affect the science.
- The experimental outlook (MATBG ∼10 meV, ν_f ∼ 0.1, T ∼ 10 K) is useful; a sentence on the expected STM spatial resolution relative to 2π/q_G and on disorder broadening of the hot spots would make the detection claim more concrete without expanding the scope.
Circularity Check
No significant circularity: QGFO period and high-T decay follow from flat-band susceptibility and second-moment identities without fitted inputs or load-bearing self-citation chains.
-
self citation load bearing
[Introduction / Eq. (7) and surrounding text; also End Matter after Eq. (A6)]
"the decay length of the QGFOs is determined by the quantum metric length ℓ_QM [31, 50–58], which is the integral of the quantum metric of the flat band as defined in Eq. (7)."
The concept and name ℓ_QM are imported from the authors’ prior works. However the present paper re-derives the second-moment identity Ω = 2a ℓ_QM from the high-T susceptibility without inserting any numerical value taken from those papers, so the citation is contextual rather than load-bearing for the central claim.
full rationale
The derivation chain is self-contained. Susceptibility is written from the T-matrix Green’s function (Eqs. 2–3), projected to the flat band, and decomposed into conventional Lindhard weight plus a quantum-distance term (Eqs. 4–5). At high T the geometric piece reduces to the Brillouin-zone-averaged quantum distance (Eq. 6), whose peaks are shown (SM Note II) to sit at the real parts of the complex poles of the flat-band projector; those poles coincide with quantum-metric hot spots when the local gap is small. The spatial extent is obtained by evaluating the second moment of the resulting negative-definite density modulation (End Matter, Eqs. A3–A6), which yields exactly Ω_QGFOs = 2a ℓ_QM once ℓ_QM is defined as the BZ integral of Tr G_f (Eq. 7). No parameter is fitted to data and then re-used as a “prediction”; the self-citations [31,50–58] merely introduce the name and prior bounds on ℓ_QM, while the present identities are re-derived from the susceptibility. Inter-band bounds (SM Note III) and intermediate-T partial averages (Eq. 10) are checked numerically on explicit models and do not close a definitional loop. Hence the only residual is ordinary self-citation of the authors’ earlier geometric-length papers, which is not load-bearing for the claimed oscillation period or temperature plateau.
Assumptions & free parameters
free parameters (3)
- δ, δ′ (or β, β′)
- t/J
- U_0
assumptions (4)
- domain assumption Non-interacting electrons; susceptibility given by the bubble with T-matrix (Eq. 2).
- domain assumption Isolated flat band: U_0, k_B T ≪ Δ_g so that interband contributions are O(1/Δ_g).
- standard math Residue theorem applied to the meromorphic structure of the projected Green function in the complex-k plane.
- domain assumption Quantum metric length ℓ_QM ≡ (V_cell/(2π)^d a) ∫ Tr G_f(k) dk bounds the imaginary part of the geometric poles.
invented entities (1)
-
quantum geometric Friedel oscillations (QGFOs)
Cite this review
Pith. "Pith review of Quantum Geometric Friedel Oscillations." pith.science (2026). https://pith.science/paper/AGIGN2PL
@misc{pith2026260704654,
author = {Pith},
title = {Pith review of: Quantum Geometric Friedel Oscillations},
year = {2026},
howpublished = {\url{https://pith.science/paper/AGIGN2PL}},
note = {Machine review of arXiv:2607.04654}
}
read the original abstract
In conventional Friedel oscillations, the real-space charge density oscillations induced by an impurity are characterized by an oscillation period set by the Fermi momentum. In this work, we show that the conventional theory is incomplete when the Bloch wavefunctions carry nontrivial quantum geometry. We demonstrate that in metals with an isolated (nearly) flat band at the Fermi energy, quantum geometry induces a distinct type of oscillations, which we call the \emph{quantum geometric Friedel oscillations} (QGFOs). The period of the QGFOs is set by the momentum space separation of the quantum metric hot spots of the flat band. The conventional and quantum metric-induced oscillations coexist at low temperatures. At higher temperatures, the conventional Friedel oscillations away from the impurity site are set by the thermal length such that the oscillations can be easily washed out by temperature effects. Remarkably, the QGFOs decay length is set by the quantum metric length which is defined by the integration of the quantum metric of the flat band. As a result, the QGFOs can persist even at temperatures much larger than the bandwidth of the flat band. Moreover, the decay length is independent of temperature for a wide range of temperatures which is a manifestation of the quantum metric protection. In conclusion, we show that the quantum metric induces novel Friedel oscillations. Our work suggests that the measurement of the QGFOs is a powerful way to detect the quantum metric length (which is associated with the integral of the quantum metric) and the quantum metric hot spot separations (which are associated with the distribution of the quantum metric in the momentum space).
Figures
Figures from the paper (3 more)
Reference graph
Works this paper leans on
-
[1]
Friedel, Il Nuovo Cimento (1955-1965)7, 287 (1958)
J. Friedel, Il Nuovo Cimento (1955-1965)7, 287 (1958)
1955
-
[2]
Bena, Comptes Rendus
C. Bena, Comptes Rendus. Physique17, 302 (2016)
2016
-
[3]
M. A. Ruderman and C. Kittel, Physical Review96, 99 (1954)
1954
-
[4]
Kasuya, Progress of theoretical physics16, 45 (1956)
T. Kasuya, Progress of theoretical physics16, 45 (1956)
1956
-
[5]
Yosida, Physical Review106, 893 (1957)
K. Yosida, Physical Review106, 893 (1957)
1957
-
[6]
N. W. Ashcroft, N. D. Mermin,et al., Solid state physics (1976)
1976
-
[7]
Kohn and J
W. Kohn and J. Luttinger, Physical Review Letters15, 524 (1965)
1965
-
[8]
G. E. Simion and G. F. Giuliani, Physical Review B72, 045127 (2005)
2005
Show all 77 references
-
[9]
Affleck, L
I. Affleck, L. Borda, and H. Saleur, Physical Review B 77, 180404 (2008)
2008
-
[10]
Grassme and P
R. Grassme and P. Bussemer, Physics Letters A175, 441 (1993)
1993
-
[11]
Cavaliere, N
F. Cavaliere, N. T. Ziani, F. Negro, and M. Sassetti, Jour- nal of Physics: Condensed Matter26, 505301 (2014)
2014
-
[12]
Egger and H
R. Egger and H. Grabert, inQuantum transport in semi- conductor submicron structures(Springer, 1996) pp. 133– 158
1996
-
[13]
A. K. Geim and I. V. Grigorieva, Nature499, 419 (2013)
2013
-
[14]
Y. Cao, V. Fatemi, S. Fang, K. Watanabe, T. Taniguchi, E. Kaxiras, and P. Jarillo-Herrero, Nature556, 43 (2018)
2018
-
[15]
J. Cai, E. Anderson, C. Wang, X. Zhang, X. Liu, W. Holtzmann, Y. Zhang, F. Fan, T. Taniguchi, K. Watanabe,et al., Nature622, 63 (2023)
2023
-
[16]
Leykam, A
D. Leykam, A. Andreanov, and S. Flach, Advances in Physics: X3, 1473052 (2018)
2018
-
[17]
P. M. Neves, J. P. Wakefield, S. Fang, H. Nguyen, L. Ye, and J. G. Checkelsky, npj Computational Materials10, 39 (2024)
2024
-
[18]
L. Ye, S. Fang, M. Kang, J. Kaufmann, Y. Lee, C. John, P. M. Neves, S. F. Zhao, J. Denlinger, C. Jozwiak,et al., Nature Physics20, 610 (2024)
2024
-
[19]
Provost and G
J. Provost and G. Vallee, Communications in Mathemat- ical Physics76, 289 (1980)
1980
-
[20]
Resta, The European Physical Journal B79, 121 (2011)
R. Resta, The European Physical Journal B79, 121 (2011)
2011
-
[21]
T¨ orm¨ a, Physical Review Letters131, 240001 (2023)
P. T¨ orm¨ a, Physical Review Letters131, 240001 (2023)
2023
-
[22]
J. Yu, B. A. Bernevig, R. Queiroz, E. Rossi, P. T¨ orm¨ a, and B.-J. Yang, npj Quantum Materials10, 101 (2025)
2025
-
[23]
Liu, X.-B
T. Liu, X.-B. Qiang, H.-Z. Lu, and X. Xie, National Sci- ence Review12, nwae334 (2025)
2025
-
[24]
Verma, P
N. Verma, P. J. Moll, T. Holder, and R. Queiroz, Nature Reviews Physics , 1 (2026)
2026
-
[25]
Peotta and P
S. Peotta and P. T¨ orm¨ a, Nature Communications6, 8944 (2015)
2015
-
[26]
Julku, S
A. Julku, S. Peotta, T. I. Vanhala, D.-H. Kim, and P. T¨ orm¨ a, Physical Review Letters117, 045303 (2016)
2016
-
[27]
X. Hu, T. Hyart, D. I. Pikulin, and E. Rossi, Physical Review Letters123, 237002 (2019)
2019
-
[28]
F. Xie, Z. Song, B. Lian, and B. A. Bernevig, Physical Review Letters124, 167002 (2020)
2020
-
[29]
Herzog-Arbeitman, V
J. Herzog-Arbeitman, V. Peri, F. Schindler, S. D. Huber, and B. A. Bernevig, Physical Review Letters128, 087002 (2022)
2022
-
[30]
T¨ orm¨ a, S
P. T¨ orm¨ a, S. Peotta, and B. A. Bernevig, Nature Reviews Physics4, 528 (2022)
2022
-
[31]
S. A. Chen and K. Law, Physical Review Letters132, 026002 (2024)
2024
-
[32]
Y. Fang, J. Cano, and S. A. A. Ghorashi, Physical Review Letters133, 106701 (2024)
2024
-
[33]
Z. Du, C. Wang, H.-P. Sun, H.-Z. Lu, and X. Xie, Nature Communications12, 5038 (2021)
2021
-
[34]
Jiang, T
Y. Jiang, T. Holder, and B. Yan, Reports on Progress in Physics88, 076502 (2025)
2025
-
[35]
Souza, T
I. Souza, T. Wilkens, and R. M. Martin, Physical Review B62, 1666 (2000). 6
2000
-
[36]
Onishi and L
Y. Onishi and L. Fu, Physical Review Research7, 023158 (2025)
2025
-
[37]
Ahn, G.-Y
J. Ahn, G.-Y. Guo, N. Nagaosa, and A. Vishwanath, Na- ture Physics18, 290 (2022)
2022
-
[38]
Verma and R
N. Verma and R. Queiroz, Proceedings of the National Academy of Sciences122, e2405837122 (2025)
2025
-
[39]
Z. Han, J. Herzog-Arbeitman, B. A. Bernevig, and S. A. Kivelson, Physical Review X14, 041004 (2024)
2024
-
[40]
Zhang, W
J.-X. Zhang, W. O. Wang, L. Balents, and L. Savary, Physical Review Letters136, 176504 (2026)
2026
-
[41]
Rossi, Current Opinion in Solid State and Materials Science25, 100952 (2021)
E. Rossi, Current Opinion in Solid State and Materials Science25, 100952 (2021)
2021
-
[42]
Sukhachov, N
P. Sukhachov, N. H. Aase, K. Mæland, and A. Sudbø, Physical Review B111, 085143 (2025)
2025
-
[43]
C.-g. Oh, T. Kitamura, A. Daido, J.-W. Rhim, and Y. Yanase, Physical Review Research8, 023096 (2026)
2026
-
[44]
Jiang and Y
G. Jiang and Y. Barlas, Physical Review Letters131, 016002 (2023)
2023
-
[45]
Sun, R.-P
Z.-T. Sun, R.-P. Yu, S. A. Chen, J.-X. Hu, and K. Law, Quantum Frontiers4, 20 (2025)
2025
-
[47]
Shavit and J
G. Shavit and J. Alicea, Physical Review Letters134, 176001 (2025)
2025
-
[48]
Kitamura, A
T. Kitamura, A. Daido, and Y. Yanase, Physical Review Letters132, 036001 (2024)
2024
-
[49]
H. Hu, O. Vafek, K. Haule, and B. A. Bernevig, Physical Review Letters136, 256505 (2026)
2026
-
[50]
J.-X. Hu, S. A. Chen, and K. T. Law, Communications Physics8, 20 (2025)
2025
-
[51]
X. Guo, X. Ma, X. Ying, and K. Law, Physical Review Letters135, 076601 (2025)
2025
-
[52]
Z. C. Li, Y. Deng, S. A. Chen, D. K. Efetov, and K. Law, Physical Review Research7, 023273 (2025)
2025
-
[54]
Ma, J.-X
X.-L. Ma, J.-X. Hu, and K. T. Law, Universal boundary- modes localization from quantum metric length (2025), arXiv:2509.05114 [cond-mat.mes-hall]
2025
-
[55]
W.-B. Dai, J. Zhao, S. A. Chen, and K. T. Law, Quan- tum metric localization and quantum metric protection (2026), arXiv:2605.03987 [cond-mat.mes-hall]
2026 arXiv
-
[56]
J. Zhao, R. Liu, X.-Y. Song, and K. T. Law, Quan- tum metric bound state of light (2026), arXiv:2606.22479 [cond-mat.mes-hall]
2026 arXiv
-
[57]
W. Chen, K. Yang, T. Cao, S.-Z. Lin, J. Yu, and D. Xiao, Quantum geometric quadrupole of cooper pairs (2026), arXiv:2605.03133 [cond-mat.supr-con]
2026 arXiv
-
[58]
S. Lee, S. H. Lee, and B.-J. Yang, Physical Review Let- ters137, 016401 (2026)
2026
-
[59]
Dutreix and M
C. Dutreix and M. Katsnelson, Physical Review B93, 035413 (2016)
2016
-
[60]
Singh, A
A. Singh, A. Datta, S. K. Das, and V. A. Singh, Physical Review B68, 235208 (2003)
2003
-
[61]
W. Chen, X. Zhou, D. Zhang, Y.-Q. Xu, and W.-K. Lou, Physical Review B110, 165413 (2024)
2024
-
[62]
Friedel oscillations with quantum geom- etry
See Supplemental Material at URL-will-be-inserted-by- publisher for 1. Friedel oscillations with quantum geom- etry. 2. Linking QGFOs wavevectors to quantum metric hot spot separations. 3. Interband susceptibilities. 4. QG- FOs in a two-band model. It includes Refs. [71–74]
-
[63]
Y. Kim, S. Flach, and A. Andreanov, Physical Review B 113, 235110 (2026)
2026
-
[64]
Marzari and D
N. Marzari and D. Vanderbilt, Physical Review B56, 12847 (1997)
1997
-
[65]
Marzari, A
N. Marzari, A. A. Mostofi, J. R. Yates, I. Souza, and D. Vanderbilt, Reviews of Modern Physics84, 1419 (2012)
2012
-
[66]
Souza, N
I. Souza, N. Marzari, and D. Vanderbilt, Physical Review B65, 035109 (2001)
2001
-
[67]
L. Liu, Y. Hong, C. Zhang, J. Zhu, J. Dong, K. Watan- abe, T. Taniguchi, L. Du, D. Shi, K. T. Law,et al., arXiv preprint arXiv:2501.06460 (2025)
2025
-
[68]
S. Geng, X. Wang, R. Guo, C. Qiu, F. Chen, Q. Wang, K. Li, P. Hao, H. Liang, Y. Huang,et al., Nature Com- munications (2026)
2026
-
[69]
Zhong, S
J. Zhong, S. Geng, T.-F. Ying, H. Li, and B. T. Zhou, Ycl electride as a multi-orbital correlated topological dice lattice system (2026), arXiv:2509.05958 [cond-mat.mtrl- sci]
2026 arXiv
-
[70]
J. G. Checkelsky, B. A. Bernevig, P. Coleman, Q. Si, and S. Paschen, Nature Reviews Materials9, 509 (2024)
2024
-
[71]
E. H. Lieb, Physical Review Letters62, 1201 (1989)
1989
-
[72]
Laubscher, C
K. Laubscher, C. S. Weber, M. H¨ unenberger, H. Schoeller, D. M. Kennes, D. Loss, and J. Klino- vaja, Physical Review B108, 155429 (2023)
2023
-
[73]
Bouzerar, Physical Review B104, 155151 (2021)
G. Bouzerar, Physical Review B104, 155151 (2021)
2021
-
[74]
Luo and M.-F
Y.-D. Luo and M.-F. Yang, Physical Review B110, 144402 (2024)
2024
-
[75]
Bochner,Vorlesungen uber fouriersche integrale (Akademische Verlagsgesellschaft, 1932)
S. Bochner,Vorlesungen uber fouriersche integrale (Akademische Verlagsgesellschaft, 1932)
1932
-
[76]
Res k=ku nf P f k Tω Res k=kl nf P f k # 1 (ω+ −E f ku nf )(ω+ −E f kl nf ) ,(S8b) Cku nf ,kl ω = Tr h Aku nf TωAkl ω i =− V 2 cell (2π)2(d−1) Tr
R. Roy, Physical Review B90, 165139 (2014). 7 END MA TTER FIG. 4. Real-space lattice and hopping structure of the 1D model. The dashed square denotes an unit cell. 1D Model and Methods.—We consider a 1D three-sublattice model with spin-diagonal Hamilto- nianH 1D = P k,σ=± Ψ† k...
2014
-
[77]
Intra-band dispersive contributions: χl(q) = 1 N X k f(E l k+q)−f(E l k) Ed k+q −E l k (1−d l k,k+q) T≪∆ g ≃ 1 N X k eEl k/T −e El k+q/T El k+q −E l k (1−d l k,k+q) ≃0, (S34) 11 FIG. S4. Inter-band susceptibilities for the 1D three-band model. (a)χ l−f and its lower bound (amp...
-
[78]
Inter-band contributions between the flat and lower dispersive bandsχ l−f: χl−f(q) = 1 N X k f(E l k+q)−f(E f k) El k+q −E f k (1−d l−f k,k+q) W f ≪T≪∆ g ≃ 1 N X k 1−e El k+q/T − 1 2(1− Ef k 2T ) El k+q −E f k (1−d l−f k,k+q) W f ≪∆g ≃ 1 N X k 1 2El k+q (1−d l−f k,k+q) ≥ − 1 2...
-
[79]
(S38) Above, we have used the approximationsf(E l k)≃1−e El k/T ,f(E h k )≃e −Eh k /T , andf(E h k )≃ 1 2(1−E f k /2T) in the regimeW f ≪T≪∆ g
Inter-band contribution between the two dispersive bands: χl−h(q) = 1 N X k f(E l k+q)−f(E h k) El k+q −E h k (1−d l−h k,k+q) T≪∆ g ≃ 1 N X k 1−e El k+q/T −e −Eh k /T El k+q −E h k (1−d l−h k,k+q) ≥ − 1 2∆g [1− ¯Dl−h(q)]. (S38) Above, we have used the approximationsf(E l k)≃1−...
1955
Reviewed July 13, 2026 · model on record in the stance chip above.
Discussion (0). Continue with ORCID to comment.