Rapid millikelvin laser cooling of in-plane motion of 2D planar Penning trap ion crystals for enhanced quantum sensing and simulation experiments

2D planar Penning trap ion crystals offer a promising platform for interacting hundreds of trapped ion qubits via their shared motional modes. However, current quantum sensing and simulation experiments¹ are challenged by the insufficient and slow cooling of planar (⊥ B) ‘ExB’ modes², which adversely impacts quantum protocol performance by broadening the axial (|| B) ‘drumhead’ mode spectra³. Our molecular dynamics-like laser cooling simulations⁴ suggest a nonlinear near-resonant mode coupling technique can be applied to cool the ExB modes to millikelvin temperatures in a few milliseconds⁵. However, since this technique operates at a higher crystal rotation frequency than typical experiments, we explore adiabatically sweeping the rotation frequency to return to ideal values without reheating. Our work paves the way for sub-Doppler laser cooling and improved quantum science experiments in 2D planar Penning trap ion crystals using a highly feasible technique.