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arxiv: 2605.23394 · v1 · pith:V4GA3LJEnew · submitted 2026-05-22 · ⚛️ physics.atom-ph

Spatial dealiasing of classical geomagnetic survey data through use of a microfabricated wearable quantum magnetometer

Stirling Scholes , Alissa Forsythe , Courtney Dyer , Amy Gilligan , Karen Lythgoe , Jenny Jenkins , Marcin Mrozowski , Jack-Andrew Smith
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Stuart Ingleby
This is my paper

Pith reviewed 2026-05-25 02:44 UTC · model grok-4.3

classification ⚛️ physics.atom-ph
keywords geomagnetic surveyoptically pumped magnetometerspatial aliasingquantum magnetometerHighland Boundary Faultnoise rejectiongeological mapping
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The pith

A wearable quantum magnetometer samples every centimeter to reduce spatial aliasing in geomagnetic surveys.

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

The paper shows that carrying an optically pumped magnetometer alongside a traditional proton precession magnetometer over a 20 km transect allows the OPM's 90 Hz continuous readings to reject noise and reveal geological features smaller than 200 m. Traditional instruments must stop for each measurement and therefore sample only every 200 m, while the OPM moves at walking speed and records data every centimeter. This denser sampling produces a hybrid dataset with higher resolution for identifying subsurface structures. The approach is presented as improving survey speed, portability, and data quality for applications such as mineral exploration.

Core claim

Walking with both instruments across the Highland Boundary Fault demonstrates that the OPM's high-bandwidth data can be used to reject magnetic noise in the PPM record and to identify previously undetected small-scale geological structures.

What carries the argument

The OPM's continuous 90 Hz sampling, which yields measurements every approximately 1 cm at 1 m/s walking speed compared with the PPM's stationary measurements every approximately 200 m.

Load-bearing premise

The additional small-scale magnetic features detected only by the OPM represent genuine geological structures rather than instrument artifacts or processing differences.

What would settle it

A follow-up high-resolution ground-truth survey or borehole sampling at the locations of the newly identified features under 200 m to test whether they correspond to actual subsurface geology.

Figures

Figures reproduced from arXiv: 2605.23394 by Alissa Forsythe, Amy Gilligan, Courtney Dyer, Jack-Andrew Smith, Jenny Jenkins, Karen Lythgoe, Marcin Mrozowski, Stirling Scholes, Stuart Ingleby.

Figure 1
Figure 1. Figure 1: a) Map of the study area across the Highland Boundary Fault (HBF) in Scotland, separating the Grampian terrane to the north from the Midland Valley (MV) terrane to the south. Inset shows this location within the United Kingdom and Northern Ireland. The solid black line marks the NW-SE trending survey profile through Blairgowrie. The red and blue squares correspond to the areas shown in b) and c), respectiv… view at source ↗
Figure 2
Figure 2. Figure 2: a) Map of the PPM (discrete squares) and OPM (continuous line) anomaly values ∆B along the survey path. The survey path transects the HBF as shown in [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: N-S profile of PPM and OPM data. PPM data is shown as coloured squares, connected by a black dashed line. OPM data is shown in green, with error bars showing the standard deviation in a 20 m window around each PPM sample point. The insets marked A, B, and C correspond to the boxed regions in the main plot. Within each inset, the OPM data is the blue line, while the PPM data is the same as the main figure. … view at source ↗
Figure 4
Figure 4. Figure 4: Forward modelling results for anomalies in the OPM data between 1.75 and 1.90 km along the survey profile (see [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Schematic of OPM sensor head. VCSEL: Vertical Cavity Surface Emitting Laser, ASL: Aspheric lens, λ/4: Quarter-wave plate, DM: Dielectric Mirror, PBS: Polarising Beam Splitter, PDs: Photodiodes. B0 denotes the external magnetic field (in this survey, Earth’s magnetic field) and BRF denotes the oscillating RF field generated by the RF coils. The angle between the incident and reflected beam is 20◦ . Inset: p… view at source ↗
read the original abstract

Geomagnetic surveys provide insight into the subsurface for a range of applications, from fundamental understanding of geological processes, to mineral exploration and locating unexploded ordnance. A persistent challenge in performing such geomagnetic surveys is the joint problem of anthropogenic noise rejection and spatial aliasing, where the limited bandwidth (< 10 Hz) of traditional surveying instruments introduces artefacts into the surveyed field. Optically Pumped Magnetometers (OPMs) exploit quantum mechanical effects to achieve highly sensitive and stable magnetic field measurements at comparatively high bandwidths. Recent advances in manufacturing have enabled OPMs to be packaged in compact and lightweight systems (approx. 1kg), that are ideal for geomagnetic surveying. Here, we show how an OPM can directly contribute to the reduction of spatial aliasing in traditional PPM data. We carry both a PPM and OPM over a 20 km long transect across the Highland Boundary Fault (HBF) in Scotland. We leverage the continuous acquisition of the OPM sampling at 90 Hz, equivalent to every approx. 1 cm at walking pace (1 m/s) versus every approx. 200 m for our PPM (which had to be stationary for measurements) to reject magnetic noise and identify new small-scale (< 200 m) geological structures. Further, we discuss the logistical advantages of the hybrid survey in terms of portability, survey delivery, data density, and data quality.

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

1 major / 0 minor

Summary. The manuscript reports results from a 20 km hybrid geomagnetic survey across the Highland Boundary Fault in Scotland, combining a traditional stationary proton precession magnetometer (PPM) with a wearable optically pumped magnetometer (OPM) operated at 90 Hz. The central claim is that the OPM's dense sampling (~1 cm spacing at walking speed) enables spatial dealiasing, anthropogenic noise rejection, and the identification of previously undetected small-scale (<200 m) geological structures, while also offering logistical advantages in portability and data density over conventional PPM surveys.

Significance. If the additional small-scale features can be shown to be genuine geological signals rather than instrumental or processing artifacts, the work would demonstrate a practical route to higher-resolution geomagnetic mapping using compact quantum sensors. This could have value for mineral exploration, UXO detection, and geological mapping where spatial aliasing currently limits survey utility.

major comments (1)
  1. [Abstract / transect results] Abstract and transect results section: the claim that the OPM data reveal new small-scale geological structures is load-bearing for the paper's contribution, yet the manuscript supplies no figures of the OPM-only features, no error bars or uncertainty quantification, no repeat transects, no comparison to independent geological maps or borehole data, and no explicit test distinguishing motion-induced or calibration artifacts from subsurface signals. Without such grounding the interpretation that the features are geological remains unverified.

Simulated Author's Rebuttal

1 responses · 2 unresolved

We thank the referee for their constructive comments on our manuscript. We address the major comment regarding the need for stronger grounding of the small-scale geological features below.

read point-by-point responses

  1. Referee: [Abstract / transect results] Abstract and transect results section: the claim that the OPM data reveal new small-scale geological structures is load-bearing for the paper's contribution, yet the manuscript supplies no figures of the OPM-only features, no error bars or uncertainty quantification, no repeat transects, no comparison to independent geological maps or borehole data, and no explicit test distinguishing motion-induced or calibration artifacts from subsurface signals. Without such grounding the interpretation that the features are geological remains unverified.

    Authors: We agree that the interpretation of the small-scale features would be strengthened by additional supporting material. In the revised manuscript we will add figures isolating the OPM-only data to display the <200 m structures, include uncertainty quantification derived from the OPM noise floor and sampling statistics, and overlay the transect results with published geological maps of the Highland Boundary Fault. We will also expand the analysis section to include an explicit assessment of motion-induced and calibration artifacts, using the simultaneous PPM data as a cross-check. However, repeat transects and borehole data were not acquired during the original field campaign. revision: partial

standing simulated objections not resolved
  • Repeat transects along the 20 km line were not performed and cannot be added retrospectively.
  • Independent borehole or other subsurface validation data for the specific features are not available to the authors.

Circularity Check

0 steps flagged

No circularity: experimental comparison only

full rationale

The paper is a field experiment comparing PPM and OPM magnetometer data along a 20 km transect. It reports continuous OPM sampling at 90 Hz versus stationary PPM points and interprets denser sampling as revealing new <200 m geological features. No equations, derivations, fitted parameters, or self-citations are invoked as load-bearing steps; the work contains no claimed first-principles result or model that reduces to its own inputs by construction. The interpretation of features as geological rather than artifactual is an empirical claim open to validation critique, but it is not circular.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard assumptions about magnetometer performance and the geological origin of magnetic anomalies; no free parameters, new entities, or ad-hoc axioms are introduced in the abstract.

axioms (2)
  • domain assumption Optically pumped magnetometers deliver accurate, high-bandwidth magnetic field measurements based on established quantum-mechanical principles.
    Invoked when claiming the OPM data can be used to correct PPM aliasing.
  • domain assumption Magnetic anomalies detected at <200 m scale along the transect are geological rather than instrumental or anthropogenic in origin.
    Required to interpret the OPM-only features as new geological structures.

pith-pipeline@v0.9.0 · 5813 in / 1385 out tokens · 60786 ms · 2026-05-25T02:44:57.522769+00:00 · methodology

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Reference graph

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