Coherent Error Suppression in Multi-Qubit Entangling Gates

TL;DR

This paper introduces a pulse shaping method using Walsh modulation to enhance the fidelity of entangling gates in trapped-ion quantum computers, effectively suppressing errors.

Contribution

It presents a novel pulse shaping technique that extends the Mølmer-Sørensen gate to suppress errors to arbitrary order, improving gate robustness.

Findings

Demonstrated Walsh modulation improves gate fidelity in experiments.

The technique suppresses frequency and timing errors effectively.

Applicable to various qubit systems coupled via harmonic modes.

Abstract

We demonstrate a simple pulse shaping technique designed to improve the fidelity of spin-dependent force operations commonly used to implement entangling gates in trapped-ion systems. This extension of the M{\o}lmer-S{\o}rensen gate can theoretically suppress the effects of certain frequency and timing errors to any desired order and is demonstrated through Walsh modulation of a two-qubit entangling gate on trapped atomic ions. The technique is applicable to any system of qubits coupled through collective harmonic oscillator modes.