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In a noisy city, you try to hear a cricket. It's quiet, and cars are humming all around. To catch its chirp, you set up a sensitive microphone and hit the noise-cancellation button. That's roughly how physicists hunt for axions — hypothetical particles that could be the very dark matter holding galaxies together.

Axions, if they exist, barely interact with ordinary matter. But in a strong magnetic field, they can briefly turn into radio waves — a faint signal at a specific frequency. The trouble is, the signal is extremely weak, and to detect it, you usually need room-sized magnets pumped with enormous energy. That's expensive, complicated, and a bit like trying to hear a cricket while a siren is blaring.

The authors propose a different route. Instead of one powerful magnet, they use a narrow solenoid tube assembled from individual rings. The key trick is to catch the signal not inside the tube but outside, using resonant circuits (LC resonators) tuned like a radio receiver to the desired frequency. This trick drastically cuts the required magnet energy while preserving the chance of catching an axion.

The new approach paves the way for an experiment in the 30–200 megahertz range (similar to FM radio frequencies). And in the future, it could enable a larger-scale search at frequencies down to 30 megahertz, where axions born in the first moments of the universe might be hiding. All this — without giant magnets and with a reasonable budget.

So the quiet cricket gets its microphone. And if it starts singing, we'll finally learn what the invisible part of the cosmos is really made of.

Original abstract

as written by the authors arXiv:2604.16602

Searches for QCD axions with masses in the neV/$$c^2$$ mass range are strongly motivated by new physics at the GUT scale and by well-motivated pre-inflationary axion symmetry breaking scales. This parameter space is challenging to probe due to the small axion-photon couplings, which typically require large, high-field magnets with substantial stored energy. In this paper, we propose a new experimental geometry based on a narrow-bore, segmented solenoid that optimizes the collection of the axion-induced signal using LC resonators outside the high-field region of the magnet bore. This alternative optimization significantly reduces the required stored magnetic energy while preserving sensitivity, enabling a near-term experiment in the 30-200 MHz (120-830 neV/$$c^2$$) range, with a cost-effective, staged scaling to a GUT-scale experiment in the 100 kHz-30 MHz (0.4-120 neV/$$c^2$$) range.