Superconducting Qubit Gates Robust to Parameter Fluctuations

TL;DR

This paper develops numerically optimized superconducting qubit gates that are resilient to parameter fluctuations and noise, significantly improving gate fidelity and stability in quantum computing.

Contribution

It introduces robust gate designs using gradient ascent pulse engineering that outperform traditional methods like DRAG in handling parameter fluctuations and noise.

Findings

Robust gates suppress errors from amplitude drifts 15 times more effectively than Gaussian pulses.

They also increase resilience to stochastic noise, improving dephasing times by up to 1.7 times.

The methods enhance gate stability under realistic fluctuating conditions.

Abstract

State-of-the-art single-qubit gates on superconducting transmon qubits can achieve the fidelities required for error-corrected computations. However, parameter fluctuations due to qubit instabilities, environmental changes, and control inaccuracies make it difficult to maintain this performance. To mitigate the effects of these parameter variations, we numerically derive gates robust to amplitude and frequency errors using gradient ascent pulse engineering (GRAPE). We analyze how fluctuations in qubit frequency, drive amplitude, and coherence affect gate performance over time. The robust pulses suppress coherent errors from drive amplitude drifts over 15 times more than a Gaussian pulse with derivative removal by adiabatic gate (DRAG) corrections. Furthermore, the robust gates, originally designed to compensate for quasi-static errors, also demonstrate resilience to stochastic, time-dependent noise, which is reflected in the dephasing time. They suppress added errors during increases in dephasing by up to 1.7 times more than DRAG.