Controlling a single motional quantum in a two-dimensional ion microtrap array

Two-dimensional arrays of ions trapped in individual, dynamically tunable microtraps are a promising technology for quantum computation and simulation. By controlling the motional excitations of the ions (phonons) in such microtrap arrays, one may be able to generate multipartite entangled states of the ions and also simulate complex Hamiltonians such as bosons in synthetic gauge fields. We trap three ⁹Be⁺ ions in a microfabricated surface electrode ion trap that generates three confining potential wells spaced 30 mm apart on the vertices of an equilateral triangle. By applying static potentials to the trap electrodes, we can individually tune the potential curvatures at each trapping site. When the motion of ions in several sites is near resonance, phonons can be transferred between sites due to the ions’ Coulomb interaction. The dynamics of a single motional excitation in the triangular array can be described either as site-localized phonons with beamsplitter-like interactions that can lead to interference, or as non-local normal modes shared between sites. Here, we report on our ability to control these single-phonon dynamics in a two-dimensional ion microtrap array. We present evidence of two ions trapped in separate sites coherently exchanging a single phonon over 100 times. We then extend the manipulation of single-phonon dynamics to all three sites by selectively tuning their curvatures and comparing experimental observations to simulations.