Refocusing two qubit gates with measurements for trapped ions

TL;DR

This paper introduces a measurement and feedback technique to improve the fidelity of two-qubit gates in trapped ion systems, overcoming limitations of traditional refocusing methods due to short noise time scales.

Contribution

The paper presents a novel measurement-based refocusing method for two-qubit gates that are resistant to conventional techniques, specifically tailored for trapped ion quantum systems.

Findings

Effective refocusing of two-qubit gates demonstrated

Method reduces noise impact in trapped ion systems

Analysis confirms applicability to relevant error models

Abstract

Dynamical decoupling techniques are the method of choice for increasing gate fidelities. While these methods have produced very impressive results in terms of decreasing local noise and increasing the fidelities of single qubit operations, dealing with the noise of two qubit gates has proven more challenging. The main obstacle is that the noise time scale is shorter than the two qubit gate itself so that refocusing methods do not work. We present a measurement and feedback based method to refocus two qubit gates which cannot be refocused by conventional methods. We analyze in detail this method for an error model which is relevant for trapped ions quantum information.