Experimental Uhrig Dynamical Decoupling using Trapped Ions

TL;DR

This paper experimentally investigates the effectiveness of Uhrig Dynamical Decoupling (UDD) sequences in protecting trapped ion qubits from phase errors, comparing its performance to CPMG sequences across various noise conditions.

Contribution

It provides the first detailed experimental comparison of UDD and CPMG sequences in a trapped ion system, including robustness against systematic errors.

Findings

UDD effectively mitigates phase errors in trapped ion qubits.

UDD shows greater robustness to systematic overrotation and detuning errors than CPMG.

Experimental results align with theoretical predictions for classical phase noise.

Abstract

We present a detailed experimental study of the Uhrig Dynamical Decoupling (UDD) sequence in a variety of noise environments. Our qubit system consists of a crystalline array of $^{9}$Be$^{+}$ ions confined in a Penning trap. We use an electron-spin-flip transition as our qubit manifold and drive qubit rotations using a 124 GHz microwave system. We study the effect of the UDD sequence in mitigating phase errors and compare against the well known CPMG-style multipulse spin echo as a function of pulse number, rotation axis, noise spectrum, and noise strength. Our results agree well with theoretical predictions for qubit decoherence in the presence of classical phase noise, accounting for the effect of finite-duration $\pi$ pulses. Finally, we demonstrate that the Uhrig sequence is more robust against systematic over/underrotation and detuning errors than is multipulse spin echo, despite the precise prescription for pulse-timing in UDD.