Ion trap quantum gates with amplitude-modulated laser beams

TL;DR

This paper introduces a new modeling approach for ion trap quantum gates using amplitude-modulated laser beams, improving robustness and performance over standard methods for optical qubits.

Contribution

A novel modeling technique for laser-ion interactions that enhances gate robustness and allows comparison of different entangling gate schemes in ion traps.

Findings

Amplitude shaping improves gate robustness against imperfections.

The new model outperforms standard techniques in describing optical qubit gates.

Comparison of $\sigma_z ext{ exttimes}\sigma_z$ and Mølmer-Sørensen gates shows performance differences.

Abstract

In ion traps, entangling gate operations can be realized by a bichromatic pair of laser beams that collectively interact with the ions. In this paper, a new method of modelling the laser-ion interaction is introduced that turns out to be superior to standard techniques for the description of gate operations on optical qubits. The treatment allows for a comparison of the performance of gates based on $\sigma_z\otimes\sigma_z$ and M{\o}lmer-S{\o}rensen interactions on optical transitions where the bichromatic laser field can be realized by an amplitude-modulated laser resonant with the qubit transition. Shaping the amplitude of the bichromatic laser pulse is shown to make the gates more robust against experimental imperfections.