# Parallel Position-Controlled Composite Quantum Logic Gates with Trapped Ions

## TL;DR

This paper presents a method for implementing parallel, high-fidelity quantum logic gates on trapped ions using nanoscale ion movement and phase control, enhancing scalability and robustness against laser inhomogeneities.

## Contribution

It introduces a simple four-pulse sequence for arbitrary single-qubit rotations that compensates for laser intensity inhomogeneities, enabling scalable parallel quantum gate operations.

## Key findings

- Achieved parallel arbitrary rotations with high fidelity.
- Demonstrated robustness against laser beam inhomogeneities.
- Enabled scalable quantum operations with a single laser modulator.

## Abstract

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 $\mu$m 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.