A team proposes a compact gravitational-wave detector based on a superconducting inductance–capacitance (LC) resonator immersed in a multi-tesla magnetic field. In the long-wavelength limit, a gravitational wave crossing a static magnetic field induces an oscillating magnetic-field perturbation proportional both to the applied field and to the gravitational-wave strain. The concept targets the 1 to 20 kHz band, a frequency range barely explored by current interferometers.

The idea revives the principle of resonant-mass detectors, but in a compact, tunable format. The authors develop a three-loop coupled-circuit model and derive the equivalent strain-noise spectrum, including thermal noise, SQUID backaction, and measurement imprecision. A superconducting pickup circuit would convert the magnetic perturbation into a flux signal, read out by a SQUID-based or quantum-limited amplifier chain.

Prototype measurements have reached a quality factor Q ≈ 5 × 10⁵, with a future target of Q = 10⁷. Under the assumed flux coupling and an idealized quantum-limited SQUID noise model, optimized circuits project strain sensitivities of order 10⁻²¹ Hz⁻¹ᐟ² over 100 Hz bands within the 1 to 20 kHz range. Increasing the active high-field volume and improving quantum-limited readout could yield further sensitivity gains.

The concept is presented as a complement to interferometric gravitational-wave searches and as motivation to investigate potential high-frequency astrophysical sources. Its tabletop scale and tunability make it especially appealing for exploring a spectral interval where expected sources are poorly known and existing detectors have limited sensitivity.