Fast pulse sequences for dynamically corrected gates in single-triplet qubits

TL;DR

This paper introduces faster, experimentally feasible pulse sequences for single-qubit gates in singlet-triplet spin qubits, incorporating dynamical error correction to enhance robustness against noise, and compares their performance with existing sequences.

Contribution

The authors develop and experimentally validate pulse sequences that are up to three times faster and more noise-robust than previous methods for singlet-triplet qubits.

Findings

New sequences are up to three times faster than existing ones.

Dynamically corrected sequences improve robustness to charge and magnetic noise.

Performance varies with noise spectrum; faster sequences excel under certain noise conditions.

Abstract

We present a set of experimentally feasible pulse sequences that implement any single-qubit gate on a singlet-triplet spin qubit and demonstrate that these new sequences are up to three times faster than existing sequences in the literature. We show that these sequences can be extended to incorporate built-in dynamical error correction, yielding gates that are robust to both charge and magnetic field noise and up to twice as fast as previous dynamically corrected gate schemes. We present a thorough comparison of the performance of our new sequences with that of several existing ones using randomized benchmarking, considering both quasistatic and $1/f^\alpha$ noise models. We provide our results both as a function of evolution time and as a function of the number of gates, which respectively yield both an effective coherence time and an estimate of the number of gates that can be performed within this coherence time. We determine which set of pulse sequences gives the best results for a wide range of noise strengths and power spectra. Overall, we find that the traditional, slower sequences perform best when there is no field noise or when the noise contains significant high-frequency components; otherwise, our new, fast sequences exhibit the best performance.