Addressed two-qubit gate interactions in microwave-driven trapped ions

Trapped ions are a promising platform for quantum computing as they can form fundamentally identical qubits with long coherence times. Quantum logic gates are often performed using lasers but can also be driven by microwave fields, for which the technology is cheaper, more reliable, and hence easier to scale up. However, due to the centimeter wavelength of microwaves, the radiation cannot be focused to a small spot size as with a laser. This complicates the addressing of qubits within a cluster of ions confined in the same potential well. Here, we demonstrate a novel electronic microwave control method to implement addressed two-qubit gates in such a register. More specifically, we demonstrate the ability to suppress a spin-dependent force using a single ion, and find the required interaction introduces 3.7(4)×10⁻⁴ error per emulated gate in a single-qubit benchmarking sequence. We model the scheme for a 17-qubit ion crystal, and find that any pair of ions should be addressable with an average crosstalk error of ∼10⁻⁵.