Spatially uniform single-qubit gate operations with near-field microwaves and composite pulse compensation

Abstract

We present a microfabricated surface-electrode ion trap with a pair of integrated waveguides that generate a standing microwave field resonant with the ^171 Yb ^+ hyperfine qubit. The waveguides are engineered to position the wave antinode near the center of the trap, resulting in maximum field amplitude and uniformity along the trap axis. By calibrating the relative amplitudes and phases of the waveguide currents, we can control the polarization of the microwave field to reduce off-resonant coupling to undesired Zeeman sublevels. We demonstrate single-qubit π -rotations as fast as 1 μ s with less than 6% variation in Rabi frequency over an 800 μ m microwave interaction region. Fully compensating pulse sequences further improve the uniformity of X -gates across this interaction region.