Multi-Qubit Gate with Trapped Ions for Microwave and Laser-Based Implementation

TL;DR

This paper proposes a robust multi-qubit gate for trapped ions using microwave and laser techniques, enhancing fidelity by mitigating magnetic field and phonon dephasing effects, suitable for scalable quantum computing.

Contribution

It introduces a new multi-qubit gate scheme in the dressed state basis that is resilient to magnetic and phonon fluctuations, applicable to both microwave and laser setups.

Findings

Gate is robust to magnetic field fluctuations.

Gate decouples from phonon dephasing.

Applicable to microwave and laser implementations.

Abstract

A proposal for a phase gate and a M{\o}lmer-S{\o}rensen (MS) gate in the dressed state basis is presented. In order to perform the multi-qubit interaction, a strong magnetic field gradient is required to couple the phonon-bus to the qubit states. The gate is performed using resonant microwave driving fields together with either a radio-frequency (RF) driving field, or additional detuned microwave driving fields. The gate is robust to ambient magnetic field fluctuations due to an applied resonant microwave driving field. Furthermore, the gate is robust to fluctuations in the microwave Rabi frequency and is decoupled from phonon dephasing due to a resonant RF or a detuned microwave driving field. This makes this new gate an attractive candidate for the implementation of high-fidelity microwave based multi-qubit gates. The proposal can also be realized in laser-based set-ups.