  The central challenge of quantum computing is implementing high-fidelity
quantum gates at scale. However, many existing approaches to qubit control
suffer from a scale-performance trade-off, impeding progress towards the
creation of useful devices. Here, we present a vision for an electronically
controlled trapped-ion quantum computer that alleviates this bottleneck. Our
architecture utilizes shared current-carrying traces and local tuning
electrodes in a microfabricated chip to perform quantum gates with low noise
and crosstalk regardless of device size. To verify our approach, we
experimentally demonstrate low-noise site-selective single- and two-qubit gates
in a seven-zone ion trap that can control up to 10 qubits. We implement
electronic single-qubit gates with 99.99916(7)% fidelity, and demonstrate
consistent performance with low crosstalk across the device. We also
electronically generate two-qubit maximally entangled states with 99.97(1)%
fidelity and long-term stable performance over continuous system operation.
These state-of-the-art results validate the path to directly scaling these
techniques to large-scale quantum computers based on electronically controlled
trapped-ion qubits.
