We propose a quantum-enhanced sensing scheme for the detection of wave-like dark matter and high-frequency gravitational waves using two-dimensional ion crystals in a Penning trap. The protocol employs spin-motion squeezed states to improve the signal-to-noise ratio and enable a super-Heisenberg scaling with respect to the number of ions over a broad parameter range. We analyze the sensitivity of the protocol to representative wave-like dark matter candidates, including the axion-like particle and the dark photon, as well as to high-frequency gravitational waves, taking into account the decoherence and dephasing of the ion spins. Our results indicate that two-dimensional ion crystals and this new protocol provide a promising platform for probing previously unexplored parameter space in searches for light dark matter and high-frequency gravitational waves.
@article{arxiv.2604.22336,
title = {Super-Heisenberg protocol for dark matter and high-frequency gravitational wave search},
author = {Wakutaka Nakano and Ryoto Takai},
journal= {arXiv preprint arXiv:2604.22336},
year = {2026}
}