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arxiv: 2605.00152 · v2 · pith:X5DO7YIVnew · submitted 2026-04-30 · 🪐 quant-ph · cond-mat.mes-hall· physics.atom-ph· physics.ins-det· physics.optics

Optically detected nuclear magnetic resonance of carbon-13 in bulk diamond

Maxwell D. Aiello , Janis Smits , Yaser Silani , Andris Berzins , David Lidsky , Bryan A. Richards , Amilcar Jeronimo Perez , Chandrasekhar Ramanathan
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Sebasti\'an C. Carrasco Jabir Chathanathil Michael Goerz Vladimir Malinovsky Dmitry Budker Sean Lourette Andrey Jarmola Victor M. Acosta
This is my paper

Pith reviewed 2026-05-09 20:22 UTC · model grok-4.3

classification 🪐 quant-ph cond-mat.mes-hallphysics.atom-phphysics.ins-detphysics.optics
keywords optically detected NMRnitrogen-vacancy centerscarbon-13 spinsLandau-Zener transitionsdiamondnuclear polarizationspin readoutquantum sensing
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The pith

Landau-Zener microwave sweeps enable optical polarization and readout of large 13C nuclear spin ensembles in diamond.

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

The paper shows how to both polarize and optically detect the states of about 10^16 carbon-13 nuclei inside ordinary bulk diamond. Rapid sweeps of microwave frequency move spin polarization back and forth between nitrogen-vacancy electron spins and more distant carbon nuclei through state-selective Landau-Zener crossings. This produces a clear change in the diamond's fluorescence that tracks the nuclear spin state and reaches over 0.5 percent peak-to-peak contrast. The nuclei maintain coherence for roughly two milliseconds, a time set mainly by relaxation of the nearby electron spins rather than by interactions among the nuclei themselves. The approach works at low magnetic fields and uses natural isotopic abundance material.

Core claim

We demonstrate a technique that allows for both optical polarization and readout of large ensembles of ~10^{16} polarized nuclear spins. Our method takes advantage of state-selective Landau-Zener transitions under microwave frequency sweeping, which bidirectionally transfer spin polarization between NV electron spins and remote 13C nuclear spins. Using natural isotopic abundance diamonds with nitrogen densities of ~0.5-10 ppm, we perform optically-detected 13C Ramsey spectroscopy and realize a nuclear-spin-dependent fluorescence contrast exceeding 0.5% peak-to-peak. We observe nuclear spin dephasing times T2*~2 ms that only modestly improve with homonuclear dipolar decoupling, indicating the

What carries the argument

Bidirectional polarization transfer via state-selective Landau-Zener transitions under microwave frequency sweeping between NV electron spins and remote 13C nuclear spins.

If this is right

  • Optical detection of 13C NMR is possible in natural-abundance diamond at millitesla or lower fields.
  • Nuclear-spin-dependent fluorescence contrast exceeds 0.5 percent peak-to-peak.
  • Nuclear dephasing times reach approximately 2 ms and are limited by longitudinal relaxation of nearby NV electron spins.
  • Each NV center effectively reads out the collective state of roughly 100 nuclei before depolarization.
  • Comparable contrast and dephasing times hold for magnetic fields between 8 and 20 mT.

Where Pith is reading between the lines

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

  • The repetitive readout character suggests the scheme could amplify weak signals from other dilute nuclear spin species in solids.
  • Mitigating NV electron relaxation, for example by additional decoupling, would likely extend the observed nuclear coherence times.
  • Because the method requires no isotopic enrichment it can be applied immediately to commercially available diamond samples.
  • The low-field operation opens routes to nuclear-spin-based precision measurements that avoid the technical demands of high-field electron-spin devices.

Load-bearing premise

The observed fluorescence contrast arises specifically from the spin states of remote 13C nuclei through efficient bidirectional Landau-Zener transfer.

What would settle it

Repeating the experiment in isotopically purified 12C diamond samples with comparable NV density but negligible 13C concentration and checking whether the fluorescence contrast disappears would test the origin of the signal.

Figures

Figures reproduced from arXiv: 2605.00152 by Amilcar Jeronimo Perez, Andrey Jarmola, Andris Berzins, Bryan A. Richards, Chandrasekhar Ramanathan, David Lidsky, Dmitry Budker, Jabir Chathanathil, Janis Smits, Maxwell D. Aiello, Michael Goerz, Sean Lourette, Sebasti\'an C. Carrasco, Victor M. Acosta, Vladimir Malinovsky, Yaser Silani.

Figure 1
Figure 1. Figure 1: (c) shows a typical ODNMR pulse sequence. During the polarization phase of the sequence, laser light is on continuously to repolarize NV centers to ms = 0, while the microwave frequency is repeatedly swept across the f+ transition unidirectionally, from low to high frequency, to transfer polarization to 13C nuclear spins. The polarization process can be understood by first considering a single NV center co… view at source ↗
Figure 2
Figure 2. Figure 2: (b) shows the averaged NV fluorescence sig￾nal time trace for three different values of τ . Each point on these plots, ∆F/F, corresponds to the average fluo￾rescence signal collected during a given laser pulse, nor￾malized to the mean fluorescence signal over the entire time trace. For τ = 0 (top, red), the nuclear spin ensem￾ble has not precessed at all between the RF pulses and experiences an overall π p… view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3 [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4 [PITH_FULL_IMAGE:figures/full_fig_p008_4.png] view at source ↗
read the original abstract

Precision measurements based on optically detected nuclear magnetic resonance offer exquisite sensitivity to absolute shifts in spin transition frequencies, with potential applications in fundamental physics experiments and inertial sensing. We investigate 13C nuclear spins in diamond as a candidate system for solid-state implementations, which hold the promise for high-fidelity readout of large numbers of coherent nuclear spins in millitesla or lower magnetic fields. We demonstrate a technique that allows for both optical polarization and readout of large ensembles of ~10^{16} polarized nuclear spins. Our method takes advantage of state-selective Landau-Zener transitions under microwave frequency sweeping, which bidirectionally transfer spin polarization between Nitrogen-Vacancy (NV) electron spins and remote 13C nuclear spins. Using natural isotopic abundance diamonds with nitrogen densities of ~0.5-10 ppm, we perform optically-detected 13C Ramsey spectroscopy and realize a nuclear-spin-dependent fluorescence contrast exceeding 0.5% peak-to-peak. We observe nuclear spin dephasing times T2*~2 ms that only modestly improve with homonuclear dipolar decoupling, indicating that they are limited by the longitudinal spin relaxation of nearby NV electron spins. We study the magnetic field dependence of the optical readout and find comparable contrast and dephasing times for magnetic fields in the range 8-20 mT. Our method can be interpreted as a type of repetitive readout, where each NV center optically reads out the spin state of ~100 nuclei before nuclear spins depolarize.

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 demonstrates a technique for both optical polarization and readout of large ensembles (~10^{16}) of 13C nuclear spins in bulk natural-abundance diamond. It employs state-selective Landau-Zener transitions driven by microwave frequency sweeps to achieve bidirectional polarization transfer between NV electron spins and remote nuclear spins, yielding a nuclear-spin-dependent fluorescence contrast exceeding 0.5% peak-to-peak. Ramsey spectroscopy reveals T2* ~2 ms that improves only modestly under homonuclear dipolar decoupling, which the authors attribute to limitation by nearby NV longitudinal relaxation; comparable performance is reported across 8–20 mT.

Significance. If the experimental results hold, the work establishes a viable route to optically detected NMR of 13C ensembles in diamond at millitesla fields, leveraging repetitive readout in which each NV interrogates ~100 nuclei before depolarization. This could enable high-sensitivity solid-state implementations for precision metrology and inertial sensing, with the bidirectional LZ mechanism and field-range data providing concrete experimental benchmarks.

major comments (2)
  1. [Abstract] Abstract: the central interpretation that observed T2* values are limited by NV longitudinal relaxation (rather than other mechanisms such as sample inhomogeneity or unaccounted dipolar interactions) is load-bearing for the dephasing claim, yet the reported outcomes provide no direct correlation or control measurement of NV T1 under the same microwave-sweep and optical conditions.
  2. [Abstract] Abstract: the assertion that the >0.5% contrast arises specifically from remote 13C spins via efficient bidirectional Landau-Zener transfer requires explicit exclusion of alternative contributions (e.g., from proximal spins or NV-related fluorescence modulation); without controls such as isotopic enrichment comparisons or NV-density variation, the attribution remains plausible but not fully secured by the presented data.
minor comments (2)
  1. [Abstract] The nitrogen densities (~0.5–10 ppm) and exact sample specifications for each dataset should be stated more precisely to allow reproducibility assessment.
  2. Inclusion of representative raw Ramsey fringes, contrast curves, and error bars on the reported T2* and contrast values would improve clarity of the experimental evidence.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their careful review and recommendation for minor revision. Their comments have prompted us to clarify the supporting evidence for our interpretations of the T2* limit and contrast origin. We respond point by point below and will incorporate revisions to the abstract and main text.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the central interpretation that observed T2* values are limited by NV longitudinal relaxation (rather than other mechanisms such as sample inhomogeneity or unaccounted dipolar interactions) is load-bearing for the dephasing claim, yet the reported outcomes provide no direct correlation or control measurement of NV T1 under the same microwave-sweep and optical conditions.

    Authors: We appreciate this observation. The manuscript infers the T2* limitation from the modest improvement under homonuclear dipolar decoupling, which rules out dominant dipolar dephasing, combined with T2* values that match expected NV T1 timescales at 8-20 mT for the employed NV densities. Field-independent performance further argues against inhomogeneity as the primary source. We acknowledge the absence of a simultaneous NV T1 measurement under identical sweep and illumination conditions. In the revision we will add a paragraph comparing our T2* to literature NV T1 data acquired under comparable optical and microwave conditions, and we will revise the abstract wording from 'indicating that they are limited by' to 'suggesting that they are limited by'. This is a partial revision relying on indirect but consistent evidence rather than new direct controls. revision: partial

  2. Referee: [Abstract] Abstract: the assertion that the >0.5% contrast arises specifically from remote 13C spins via efficient bidirectional Landau-Zener transfer requires explicit exclusion of alternative contributions (e.g., from proximal spins or NV-related fluorescence modulation); without controls such as isotopic enrichment comparisons or NV-density variation, the attribution remains plausible but not fully secured by the presented data.

    Authors: We agree that explicit exclusion of alternatives would strengthen the claim. The reported ~100 nuclei per NV, obtained by dividing the total polarized ensemble size (~10^16) by the NV density, is incompatible with a dominant contribution from the small number of proximal spins that experience strong hyperfine couplings. The Landau-Zener sweeps are tuned to the weak-coupling regime, and the observed Ramsey frequency precisely matches the 13C Larmor frequency, inconsistent with NV fluorescence modulation. Proximal-spin dynamics would produce different sweep-rate dependence and would not support the bidirectional transfer we demonstrate. We do not have 13C-enriched or depleted samples for direct comparison. In the revision we will add a supplementary subsection with quantitative estimates showing why proximal couplings and unrelated modulation are incompatible with the observed contrast magnitude, sweep parameters, and nuclear-frequency selectivity. We will also revise the abstract to state that the contrast is consistent with remote 13C spins. This constitutes a partial revision. revision: partial

Circularity Check

0 steps flagged

No significant circularity

full rationale

The paper is a purely experimental demonstration of optically detected 13C NMR in diamond using NV centers via Landau-Zener sweeps. No equations, derivations, first-principles predictions, or fitted parameters are presented that could reduce to inputs by construction. All reported quantities (fluorescence contrast >0.5%, T2*~2 ms, field dependence) are direct measurements. The repetitive-readout interpretation is post-hoc and does not involve any self-referential logic or self-citation chains. This is the normal case of a self-contained experimental result with score 0.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard spin physics and established NV-center properties with no free parameters, new axioms, or invented entities introduced by the paper.

axioms (2)
  • standard math Landau-Zener transition physics for spin systems under frequency sweeps
    Invoked to explain bidirectional polarization transfer between NV electrons and 13C nuclei.
  • domain assumption NV center optical pumping and readout mechanisms
    Standard properties of NV centers in diamond used for polarization and fluorescence detection.

pith-pipeline@v0.9.0 · 5651 in / 1346 out tokens · 115341 ms · 2026-05-09T20:22:18.401198+00:00 · methodology

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