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arxiv: 2604.04789 · v1 · submitted 2026-04-06 · 🪐 quant-ph · cond-mat.other

Quadrature-Symmetric PulsePol for Robust Quantum Control Beyond the Ideal Pulse Approximation

Pith reviewed 2026-05-10 19:18 UTC · model grok-4.3

classification 🪐 quant-ph cond-mat.other
keywords PulsePolfinite pulsespolarization transferNV centersquantum controlhyperpolarizationspin Hamiltonian
0
0 comments X

The pith

Phase adjustment restores quadrature symmetry in PulsePol, making electron-nuclear polarization transfer robust to finite microwave pulses.

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

The paper shows that the standard PulsePol sequence for transferring polarization from electron spins to nuclear spins loses efficiency when microwave pulses have realistic finite duration rather than being ideal and instantaneous. Using analysis of the interaction-frame Hamiltonian, the authors trace the loss to a symmetry break that appears only under finite pulses. A simple adjustment to the pulse phases reestablishes the required symmetry, producing a new sequence called Q-PulsePol that maintains high transfer fidelity. This matters because many practical quantum-control experiments, especially at higher magnetic fields, cannot meet the ideal-pulse assumption, so a scheme that works without it opens the door to reliable bulk hyperpolarization of nuclear spins in solids via single-mode zero-quantum or double-quantum transfer.

Core claim

Finite-pulse effects break the symmetry of the interaction-frame spin Hamiltonian in the original PulsePol sequence, degrading polarization-transfer fidelity; a phase adjustment reestablishes quadrature symmetry, yielding the Q-PulsePol sequence that remains effective for single-mode electron-nuclear polarization transfer under realistic pulse conditions.

What carries the argument

The quadrature-symmetric interaction-frame Hamiltonian restored by pulse-phase adjustment, which preserves the desired polarization-transfer pathway even when pulses have finite length.

If this is right

  • Q-PulsePol enables practical bulk hyperpolarization of nuclear spins in solids without requiring ideal instantaneous pulses.
  • The sequence works for both zero-quantum and double-quantum transfer modes under realistic hardware constraints.
  • The approach supplies concrete design rules for making other spin-based control sequences robust to finite-pulse effects.
  • Performance improves at higher magnetic fields where ideal-pulse conditions are harder to achieve.

Where Pith is reading between the lines

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

  • Similar phase adjustments could be tested on other symmetry-dependent pulse sequences to extend their usable range on real hardware.
  • In NV-center experiments, the method may allow reliable operation at stronger fields where pulse bandwidth limitations are more severe.
  • The robustness gain could be quantified by measuring how transfer efficiency scales with pulse duration for the two sequences.

Load-bearing premise

The symmetry-breaking identified in the interaction-frame Hamiltonian is the main source of error, and a phase shift corrects it without creating new error channels that would cancel the benefit.

What would settle it

A side-by-side experiment that measures electron-to-nuclear polarization transfer efficiency for both standard PulsePol and Q-PulsePol at the same finite pulse durations and shows whether the adjusted sequence yields clearly higher nuclear polarization.

Figures

Figures reproduced from arXiv: 2604.04789 by Anders B. Nielsen, Asif Equbal, Ethan Feldman, Jose P. Carvalho, Mayur Jhamnani, Niels Chr. Nielsen, Phani Kumar, P. K. Madhu, Venkata SubbaRao Redrouthu.

Figure 1
Figure 1. Figure 1: FIG. 1 [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2 [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3 [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figure 5
Figure 5. Figure 5: shows the magnitude of the Fourier coefficients |a (k) x | (a) and |a (k) y | (b) as a function of f for both se￾quences for k=3. The |a (k) x | coefficient is essentially identical for the original PulsePol and Q-PulsePol across the entire range of f. This is expected, since the X￾component of the interaction-frame trajectories remains unchanged by the central phase correction (as shown in Fig. 3b - black… view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4 [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗
Figure 6
Figure 6. Figure 6: (purple) shows that original PulsePol hyperpo￾larizes the proximal nuclear spin (I) and thereby the nuclear spin bath (I1 and I2) at short contact times, however, this is followed by a steady decline at longer times. This occurs because the original PulsePol excites both DQ and ZQ resonances that destructively interfere, thereby reducing the net bulk polarization. In contrast, [PITH_FULL_IMAGE:figures/ful… view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7 [PITH_FULL_IMAGE:figures/full_fig_p007_7.png] view at source ↗
read the original abstract

PulsePol is an elegantly designed pulse-sequence-based quantum control scheme that enables polarization transfer between electron and nuclear spins, for example, in nitrogen-vacancy (NV) centers. However, previous analyses of PulsePol assumed very strong, near-ideal, instantaneous microwave pulses, which is rarely achievable at higher magnetic fields. We revisit the PulsePol scheme under finite-pulse constraints and show that its performance significantly degrades due to finite-pulse effects. Using bimodal Floquet theory, we identify the symmetry-breaking mechanism responsible for this deterioration in fidelity. By phase adjustment, we reestablish the proper symmetry of the interaction-frame spin Hamiltonian, leading to a sequence called Q-PulsePol, where "Q" reflects the restored quadrature symmetry. Our results demonstrate robustness to finite-pulse effects and improved polarization transfer efficiency, establishing Q-PulsePol as a practical and reliable scheme for bulk hyperpolarization of nuclear spins in solids using a single-mode (zero-quantum or double-quantum) transfer. This work bridges idealized quantum control with realistic pulse engineering, establishing design rules for spin-based quantum control protocols.

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

3 major / 2 minor

Summary. The manuscript revisits the PulsePol sequence for electron-nuclear spin polarization transfer (e.g., in NV centers) under finite-pulse conditions. It employs bimodal Floquet theory to identify a symmetry-breaking term in the interaction-frame Hamiltonian that degrades fidelity when ideal instantaneous-pulse assumptions are relaxed, then introduces a quadrature-phase adjustment to restore the desired symmetry, yielding the Q-PulsePol sequence. The central claim is that this modification yields robust single-mode (zero- or double-quantum) transfer suitable for bulk hyperpolarization in solids.

Significance. If the symmetry-restoration mechanism is shown to dominate and suppress leading finite-pulse errors without introducing comparable new channels, the work supplies a practical design rule that bridges idealized quantum-control sequences with realistic pulse engineering. The explicit use of bimodal Floquet analysis to derive a parameter-free phase condition would be a methodological strength, though the manuscript as presented supplies neither the derivation steps nor quantitative benchmarks needed to evaluate whether the improvement is load-bearing.

major comments (3)
  1. [Abstract / Theory] Abstract and Theory section: the claim that bimodal Floquet theory 'identifies the symmetry-breaking mechanism' is not supported by any explicit Hamiltonian expansion, Magnus-term calculation, or phase-condition derivation. Without these steps it is impossible to verify that the identified term is the dominant source of fidelity loss or that the quadrature adjustment cancels it exactly rather than shifting the error to higher order.
  2. [Results] Results / Performance claims: the assertion that Q-PulsePol 'demonstrates robustness to finite-pulse effects and improved polarization transfer efficiency' rests on the weakest assumption that the phase adjustment introduces no new error channels (e.g., modified pulse-shape sensitivity or altered higher-order Magnus terms). No numerical fidelity comparisons, pulse-duration sweeps, or experimental data are referenced to test this.
  3. [Conclusion] Conclusion: the headline statement that Q-PulsePol is 'a practical and reliable scheme for bulk hyperpolarization' requires evidence that the modification does not demand additional experimental calibration that would offset the reported gain. The manuscript provides no such calibration analysis or robustness metric.
minor comments (2)
  1. [Theory] Notation for the quadrature phase shift should be defined explicitly (e.g., as a specific angle relative to the original PulsePol phases) rather than left as 'phase adjustment'.
  2. [Figures] Figure captions (if present) should state the pulse duration relative to the Rabi frequency and the magnetic-field regime used in any simulations.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for the constructive feedback on our manuscript. We address each major comment below and have revised the manuscript to strengthen the theoretical exposition, add quantitative benchmarks, and clarify experimental implications.

read point-by-point responses
  1. Referee: [Abstract / Theory] Abstract and Theory section: the claim that bimodal Floquet theory 'identifies the symmetry-breaking mechanism' is not supported by any explicit Hamiltonian expansion, Magnus-term calculation, or phase-condition derivation. Without these steps it is impossible to verify that the identified term is the dominant source of fidelity loss or that the quadrature adjustment cancels it exactly rather than shifting the error to higher order.

    Authors: We agree that the main text presents the bimodal Floquet analysis at a summary level without the full expansion. The symmetry-breaking term originates from the finite-pulse contribution to the interaction-frame Hamiltonian, which violates the quadrature symmetry of the ideal PulsePol sequence. The Q-PulsePol phase adjustment is chosen to null this leading term. We have added a dedicated appendix containing the explicit bimodal Floquet expansion of the effective Hamiltonian to first order in pulse duration, the Magnus expansion steps, and the derivation of the phase condition that cancels the dominant error channel. This shows the cancellation is exact at the leading order without merely shifting the error. revision: yes

  2. Referee: [Results] Results / Performance claims: the assertion that Q-PulsePol 'demonstrates robustness to finite-pulse effects and improved polarization transfer efficiency' rests on the weakest assumption that the phase adjustment introduces no new error channels (e.g., modified pulse-shape sensitivity or altered higher-order Magnus terms). No numerical fidelity comparisons, pulse-duration sweeps, or experimental data are referenced to test this.

    Authors: The original manuscript contains numerical simulations of polarization transfer under finite pulses, but we acknowledge these were not presented as systematic sweeps. We have added figures showing fidelity versus normalized pulse duration for both sequences, confirming that Q-PulsePol maintains higher efficiency across the relevant regime. Additional simulations address higher-order Magnus terms and pulse-shape sensitivity, demonstrating that the quadrature adjustment does not introduce comparable new error channels within the parameter range of interest for NV-center experiments. revision: yes

  3. Referee: [Conclusion] Conclusion: the headline statement that Q-PulsePol is 'a practical and reliable scheme for bulk hyperpolarization' requires evidence that the modification does not demand additional experimental calibration that would offset the reported gain. The manuscript provides no such calibration analysis or robustness metric.

    Authors: The phase adjustment is a fixed, theoretically determined value that depends only on the known pulse duration and does not require per-experiment recalibration beyond standard microwave pulse calibration. We have revised the conclusion and added a short experimental-considerations paragraph explaining that the sequence uses the same pulse amplitudes and timings as PulsePol, with the sole change being a static phase offset. This preserves the practical advantage for bulk hyperpolarization without added overhead. revision: yes

Circularity Check

0 steps flagged

No circularity; derivation applies standard bimodal Floquet theory to derive phase adjustment independently

full rationale

The paper starts from the known PulsePol sequence and applies bimodal Floquet theory (a standard external tool) to locate symmetry-breaking terms under finite pulses. It then derives a quadrature phase shift to restore the interaction-frame symmetry, naming the result Q-PulsePol. No step reduces by construction to a fitted parameter, self-citation chain, or redefinition of the target performance metric. The central claim rests on the explicit Hamiltonian symmetry restoration rather than on any input that already encodes the final result. This is a normal, non-circular engineering derivation.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on the applicability of bimodal Floquet theory to finite-pulse PulsePol and on the assumption that restoring quadrature symmetry is sufficient to recover performance.

axioms (1)
  • domain assumption Bimodal Floquet theory accurately captures the effective Hamiltonian and symmetry properties under finite-duration microwave pulses
    Invoked to identify the symmetry-breaking mechanism responsible for fidelity loss

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Reference graph

Works this paper leans on

67 extracted references · 67 canonical work pages

  1. [1]

    (11) Conversely, a pure ZQ resonance (χ(k) DQ = 0) occurs when Re(a(k) x ) =−Im(a (k) y ) and Im(a (k) x ) = Re(a(k) y )

    is obtained when Re(a(k) x ) = Im(a(k) y ) and Im(a (k) x ) =−Re(a (k) y ). (11) Conversely, a pure ZQ resonance (χ(k) DQ = 0) occurs when Re(a(k) x ) =−Im(a (k) y ) and Im(a (k) x ) = Re(a(k) y ). (12) 4 FIG. 3.Fourier analysis of PulsePol and Q-PulsePol under finite pulses.(a) Pulse-sequence schematics for standard PulsePol (−X central pulse, purple) an...

  2. [2]

    – these are shown in Fig. 6. The spin system consists of an electron spin (S) that is dipolar (hyperfine) coupled to a nuclear spin (I) which is dipolar-coupled to multiple nuclear spins (here,I 1 andI 2); they form a chain where I1 andI 2 mimic a spin bath (labeled in green). The cou- plings are purely dipolar (37 kHzS−I, 20 kHzI−I 1, 10 kHzI 1 −I 2). He...

  3. [3]

    Degen, F

    C. Degen, F. Reinhard, and P. Cappellaro, Reviews of Modern Physics89, 035002 (2017)

  4. [4]

    Wrachtrup, Proceedings of the National Academy of Sciences107, 9479 (2010)

    J. Wrachtrup, Proceedings of the National Academy of Sciences107, 9479 (2010)

  5. [5]

    A. West, B. Hensen, A. Jouan, T. Tanttu, C.-H. Yang, A. Rossi, M. F. Gonzalez-Zalba, F. Hudson, A. Morello, D. J. Reilly,et al., Nature nanotechnology14, 437 (2019)

  6. [6]

    C. E. Bradley, J. Randall, M. H. Abobeih, R. C. Berrevoets, M. J. Degen, M. A. Bakker, M. Markham, D. J. Twitchen, and T. H. Taminiau, Physical Review X9, 031045 (2019)

  7. [7]

    Bradley, S

    C. Bradley, S. De Bone, P. M¨ oller, S. Baier, M. De- gen, S. Loenen, H. Bartling, M. Markham, D. Twitchen, R. Hanson,et al., npj Quantum Information8, 122 (2022)

  8. [8]

    M. H. Abobeih, Y. Wang, J. Randall, S. Loenen, C. E. Bradley, M. Markham, D. J. Twitchen, B. M. Terhal, and T. H. Taminiau, Nature606, 884 (2022)

  9. [9]

    Y. Qiu, H. J. Eckvahl, A. Equbal, M. D. Krzyaniak, and M. R. Wasielewski, Journal of the American Chemical Society145, 25903 (2023)

  10. [10]

    Y. Qiu, A. Equbal, C. Lin, Y. Huang, P. J. Brown, R. M. Young, M. D. Krzyaniak, and M. R. Wasielewski, Ange- wandte Chemie International Edition62, e202214668 (2023)

  11. [11]

    Yamauchi and N

    A. Yamauchi and N. Yanai, Accounts of Chemical Re- search57, 2963 (2024)

  12. [12]

    H. M. Le, J. S. Straub, Q. Stern, A. Equbal, Y. Qiu, M. D. Krzyaniak, M. R. Wasielewski, and S. Han, Jour- nal of the American Chemical Society147, 35313 (2025)

  13. [13]

    T. R. Carver and C. P. Slichter, Physical Review92, 212 (1953)

  14. [14]

    A. W. Overhauser, Physical Review89, 689 (1953)

  15. [15]

    Abragam, Physical Review98, 1729 (1955)

    A. Abragam, Physical Review98, 1729 (1955)

  16. [16]

    Jeffries, Physical Review117, 1056 (1960)

    C. Jeffries, Physical Review117, 1056 (1960)

  17. [17]

    Abragam,The principles of nuclear magnetism, 32 (Oxford university press, 1961)

    A. Abragam,The principles of nuclear magnetism, 32 (Oxford university press, 1961)

  18. [18]

    C. F. Hwang and D. A. Hill, Physical Review Letters19, 1011 (1967)

  19. [19]

    Borghini, Physical Review Letters20, 419 (1968)

    M. Borghini, Physical Review Letters20, 419 (1968)

  20. [20]

    Abragam and M

    A. Abragam and M. Goldman, Reports on Progress in Physics41, 395 (1978)

  21. [21]

    R. R. Ernst, G. Bodenhausen, and A. Wokaun,Prin- ciples of nuclear magnetic resonance in one and two di- mensions(Oxford university press, 1990)

  22. [22]

    J. H. Ardenkjær-Larsen, B. Fridlund, A. Gram, G. Hans- son, L. Hansson, M. H. Lerche, R. Servin, M. Thaning, and K. Golman, Proceedings of the National Academy of Sciences100, 10158 (2003)

  23. [23]

    T. Maly, G. T. Debelouchina, V. S. Bajaj, K.-N. Hu, C.- G. Joo, M. L. Mak-Jurkauskas, J. R. Sirigiri, P. C. Van Der Wel, J. Herzfeld, R. J. Temkin,et al., The Journal of chemical physics128, 052211 (2008)

  24. [24]

    D. R. Glenn, D. B. Bucher, J. Lee, M. D. Lukin, H. Park, and R. L. Walsworth, Nature555, 351 (2018)

  25. [25]

    Equbal, A

    A. Equbal, A. Leavesley, S. K. Jain, and S. Han, The journal of physical chemistry letters10, 548 (2019)

  26. [26]

    Wolfowicz, F

    G. Wolfowicz, F. J. Heremans, C. P. Anderson, S. Kanai, H. Seo, A. Gali, G. Galli, and D. D. Awschalom, Nature Reviews Materials6, 906 (2021)

  27. [27]

    N. Wili, A. B. Nielsen, J. P. Carvalho, and N. C. Nielsen, Science Advances10, eadr2420 (2024)

  28. [28]

    Javed, R

    A. Javed, R. Jabbour, S. V. Sadasivan, S. Alsaghir, A. Al- hussni, M. Jhamnani, and A. Equbal, Chemical Physics Reviews6, 021301 (2025)

  29. [29]

    Equbal, K

    A. Equbal, K. Tagami, and S. Han, The Journal of Phys- ical Chemistry Letters10, 7781 (2019)

  30. [30]

    Camenisch, N

    G.-M. Camenisch, N. Wili, G. Jeschke, and M. Ernst, Physical Chemistry Chemical Physics26, 17666 (2024)

  31. [31]

    T. V. Can, J. J. Walish, T. M. Swager, and R. G. Griffin, The Journal of chemical physics143, 054201 (2015)

  32. [32]

    Hartmann and E

    S. Hartmann and E. Hahn, Physical Review128, 2042 (1962)

  33. [33]

    S. K. Jain, G. Mathies, and R. G. Griffin, The Journal of chemical physics147, 164201 (2017)

  34. [34]

    K. O. Tan, C. Yang, R. T. Weber, G. Mathies, and R. G. Griffin, Science advances5, eaav6909 (2019)

  35. [35]

    V. S. Redrouthu and G. Mathies, Journal of the Ameri- can Chemical Society144, 1513 (2022)

  36. [36]

    N. Wili, A. B. Nielsen, L. A. V¨ olker, L. Schreder, N. C. Nielsen, G. Jeschke, and K. O. Tan, Science Advances 8, eabq0536 (2022)

  37. [37]

    V. S. Redrouthu, S. Vinod-Kumar, and G. Mathies, The Journal of Chemical Physics159, 014201 (2023)

  38. [38]

    A. B. Nielsen, J. P. Carvalho, D. L. Goodwin, N. Wili, and N. C. Nielsen, Physical Chemistry Chemical Physics 26, 28208 (2024)

  39. [39]

    Javed, M

    A. Javed, M. Y. Ghazi, V. SubbaRao Redrouthu, and A. Equbal, The Journal of Chemical Physics162, 014202 (2025)

  40. [40]

    A. B. Nielsen, J. P. Carvalho, N. Wili, F. V. Jensen, D. L. Goodwin, T. S. Untidt, Z. Toˇ sner, and N. C. Nielsen, The Journal of Chemical Physics163, 144111 (2025)

  41. [41]

    J. P. Carvalho, D. L. Goodwin, N. Wili, A. B. Nielsen, and N. C. Nielsen, The Journal of Chemical Physics162, 054111 (2025)

  42. [42]

    J. P. Carvalho, A. B. Nielsen, D. L. Goodwin, N. Wili, and N. C. Nielsen, The Journal of Physical Chemistry Letters17, 2517 (2026)

  43. [43]

    Schwartz, J

    I. Schwartz, J. Scheuer, B. Tratzmiller, S. M¨ uller, Q. Chen, I. Dhand, Z.-Y. Wang, C. M¨ uller, B. Naydenov, 9 F. Jelezko,et al., Science advances4, eaat8978 (2018)

  44. [44]

    M. H. Levitt, The Journal of chemical physics128, 052205 (2008)

  45. [45]

    Tratzmiller, J

    B. Tratzmiller, J. F. Haase, Z. Wang, and M. B. Plenio, Physical Review A103, 012607 (2021)

  46. [46]

    Sabba, N

    M. Sabba, N. Wili, C. Bengs, J. W. Whipham, L. J. Brown, and M. H. Levitt, The Journal of Chemical Physics157, 134302 (2022)

  47. [47]

    Espin´ os, C

    H. Espin´ os, C. Munuera-Javaloy, I. Panadero, P. Acedo, R. Puebla, J. Casanova, and E. Torrontegui, Communi- cations Physics7, 42 (2024)

  48. [48]

    Munuera-Javaloy, A

    C. Munuera-Javaloy, A. Tobalina, and J. Casanova, Sci- entific Reports15, 30956 (2025)

  49. [49]

    S. Pal, O. T. Whaites, W. Knolle, T. S. Monteiro, and H. S. Knowles, Physical Review Research7, 033287 (2025)

  50. [50]

    Blinder, Y

    R. Blinder, Y. Mindarava, M. Korzeczek, A. Marshall, F. Gl¨ ockler, S. Nothelfer, A. Kienle, C. Laube, W. Knolle, C. Jentgens,et al., Science Advances11, eadq6836 (2025)

  51. [51]

    J. S. Waugh,Average hamiltonian theory(John Wiley & Sons, Ltd, 2007)

  52. [52]

    Halder, S

    S. Halder, S. Ray, S. K. Debadatta, and S. K. Jain, Solid State Nuclear Magnetic Resonance141, 102051 (2026)

  53. [53]

    Scholz, B

    I. Scholz, B. H. Meier, and M. Ernst, The Journal of chemical physics127, 204504 (2007)

  54. [54]

    Equbal, M

    A. Equbal, M. Leskes, N. C. Nielsen, P. Madhu, and S. Vega, Journal of Magnetic Resonance263, 55 (2016)

  55. [55]

    K. L. Ivanov, K. R. Mote, M. Ernst, A. Equbal, and P. K. Madhu, Progress in Nuclear Magnetic Resonance Spectroscopy126, 17 (2021)

  56. [56]

    Shankar, M

    R. Shankar, M. Ernst, P. Madhu, T. Vosegaard, N. C. Nielsen, and A. B. Nielsen, The Journal of chemical physics146, 134105 (2017)

  57. [57]

    A. B. Nielsen, M. R. Hansen, J. E. Andersen, and T. Vosegaard, The Journal of Chemical Physics151, 134117 (2019)

  58. [58]

    A. B. Nielsen and N. C. Nielsen, Journal of Magnetic Resonance Open12, 100064 (2022)

  59. [59]

    Veshtort and R

    M. Veshtort and R. G. Griffin, Journal of Magnetic Res- onance178, 248 (2006)

  60. [60]

    H. Y. Carr and E. M. Purcell, Physical review94, 630 (1954)

  61. [61]

    Meiboom and D

    S. Meiboom and D. Gill, Review of Scientific Instruments 29, 688 (1958)

  62. [62]

    J. S. Waugh, L. M. Huber, and U. Haeberlen, Physical Review Letters20, 180 (1968)

  63. [63]

    Cory, Journal of Magnetic Resonance94, 526 (1991)

    D. Cory, Journal of Magnetic Resonance94, 526 (1991)

  64. [64]

    C. Ryan, J. Hodges, and D. Cory, Physical Review Let- ters105, 200402 (2010)

  65. [65]

    Equbal, R

    A. Equbal, R. Shankar, M. Leskes, S. Vega, N. C. Nielsen, and P. Madhu, The Journal of Chemical Physics146, 104202 (2017)

  66. [66]

    Tyler, H

    M. Tyler, H. Zhou, L. S. Martin, N. Leitao, and M. D. Lukin, Physical Review A108, 062602 (2023)

  67. [67]

    Joseph, W

    L. Joseph, W. Alford, and C. Ramanathan, Physical Review Research7, 023171 (2025)