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

TL;DR

This paper introduces a microfabricated ion trap with integrated waveguides that produce a uniform microwave field for precise single-qubit operations, enhanced by composite pulse sequences for improved gate fidelity.

Contribution

It demonstrates a novel trap design with integrated waveguides for uniform microwave control and applies composite pulses to enhance gate uniformity and fidelity.

Findings

Achieved 1 microsecond single-qubit rotations with less than 6% Rabi frequency variation.

Engineered waveguides produce a uniform microwave field over 800 micrometers.

Composite pulse sequences improve gate uniformity across the interaction region.

Abstract

We present a microfabricated surface-electrode ion trap with a pair of integrated waveguides that generate a standing microwave field resonant with the 171Yb+ 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 pi-rotations as fast as 1 us with less than 6 % variation in Rabi frequency over an 800 um microwave interaction region. Fully compensating pulse sequences further improve the uniformity of X-gates across this interaction region.