Motional Squeezing of a 2D Ion Crystal via Parametric Amplification

Improving coherence is a fundamental challenge in quantum simulations and sensing experiments on trapped ions.  Here we discuss preliminary experiments attempting to enhance the spin-motion coupling of ions via parametric amplification without a reduction in the spin coherence.  These experiments are performed on 2D crystal arrays of over a hundred Be⁺ ions confined in a Penning trap.  This device has been used to perform quantum simulations and sense displacements of the ion crystal that are small compared to the ground state zero-point fluctuations.  By oscillating the trapping potential at close to twice the center-of-mass mode frequency, we can squeeze the motional mode, which will enhance the spin-motion coupling while maintaining the spin coherence.  This will enable higher fidelity simulations and improve our sensitivity to small displacements.