Researchers propose a significant improvement for high-frequency gravitational wave detectors, known as magnetic Weber bars. These devices aim to detect mechanical deformations in large magnets induced by the passage of a gravitational wave. The new proposal incorporates magnetic field configurations with strong gradients, such as Halbach arrays, which, despite having lower field strengths, increase detector efficiency by maximizing interaction with the gravitational wave.

The study focuses on detecting short-duration, low-coherence signals, particularly the ring-down period of mechanical resonators, which are among the most challenging yet realistic events. Results indicate that, with current technology, this setup could achieve sensitivities of $S_h^{1/2} \simeq 10^{-21}/\sqrt{\text{Hz}}$ across a broad set of frequencies around resonance peaks at $\sim 10$ kHz. For broadband searches at higher frequencies, the estimated sensitivity is $S_h^{1/2} \simeq 5 \cdot 10^{-20}/\sqrt{\text{Hz}}$.

The authors also discuss plausible future upgrades to reach sensitivities of $S_h^{1/2} \simeq (10^{-23} - 10^{-21})/\sqrt{\text{Hz}}$ in a broadband search covering 10 kHz to the MHz range. This advance is crucial for exploring the gravitational universe in a frequency spectrum different from current detectors like LIGO or Virgo, opening the door to detecting astrophysical phenomena such as the coalescence of intermediate-mass black holes or processes in the early universe.