We demonstrate parallel composite quantum logic gates with phases implemented locally through nanoscale movement of ions within a global laser beam of fixed pulse duration. We show that a simple four-pulse sequence suffices for constructing ideal arbitrary single-qubit rotations in the presence of large intensity inhomogeneities across the ion trap due to laser beam-pointing or beam-focusing. Using such sequences, we perform parallel arbitrary rotations on ions in two trapping zones separated by 700 μm with fidelities comparable to those of our standard laser-controlled gates. Our scheme improves on current transport or zone-dependent quantum gates to include phase modulation with local control of the ion's confinement potential. This enables a scalable implementation of an arbitrary number of parallel operations on densely packed qubits with a single laser modulator and beam path.
@article{arxiv.1702.03568,
title = {Parallel Position-Controlled Composite Quantum Logic Gates with Trapped Ions},
author = {Michael S. Gutierrez and Guang Hao Low and Richard Rines and Helena Zhang},
journal= {arXiv preprint arXiv:1702.03568},
year = {2017}
}