Holographic optical manipulation of trapped-ion qubits for minimizing crosstalk errors in quantum processors

Trapped ions are among the most advanced platforms for quantum computation and simulation. Programmable, flexible and precise control over each ion is required to efficiently implement arbitrary quantum gates and simulate Hamiltonians. An important fundamental challenge towards this individual control is the unavoidable `crosstalk error’ due to micron-level inter-ion separation. Here, we present experimental results [1] from a holographic optical ion-addressing setup for Yb⁺ ions (λ = 369.5 nm) using a Digital Micromirror Device (DMD). This technique uses a reprogrammable hologram to modulate the wavefront of the addressing beam and thus engineer an adaptable and accurate amplitude and phase profile of light across the ions. Using a single ion as an aberration sensor, we compensate all aberrations to better than λ/20 and produce <10^-4 intensity crosstalk error in arbitrary pair-wise addressing profiles. Such high-precision optical control will enable the simulation of arbitrary and dynamic lattice geometries of spins to be realized in a 1D chain of ions. This scheme relies on standard commercial hardware, can be readily extended to over a hundred ions, and adapted to other ion-species and platforms.