Compact Pulse Schedules for High-Fidelity Single-Flux Quantum Qubit Control

TL;DR

This paper introduces compact SFQ pulse schedules for high-fidelity single-flux quantum qubit control, reducing memory requirements and maintaining over 99.99% fidelity, thus enhancing scalability and efficiency.

Contribution

It extends the DRAG framework to SFQ-controlled qubits, enabling high-fidelity gates with minimal control sequence memory.

Findings

Pulse sequences stored in 22 bits or fewer

Gate fidelities exceed 99.99%

Reduced control hardware footprint

Abstract

In the traditional approach to controlling superconducting qubits using microwave pulses, the field of pulse shaping has emerged in order to assist in the removal of leakage and increase gate fidelity. However, the challenge of scaling microwave control electronics has created an opportunity to explore alternative methods such as single-flux quantum (SFQ) pulses. For qubits controlled by SFQ pulses, high fidelity gates can be achieved by optimizing the binary control sequence. We extend the notion of the derivative removal by adiabatic gate (DRAG) framework a transmon qubit controlled by SFQ drivers. The proposed implementation of SFQ pulse sequences can be stored in 22 bits or fewer, with gate fidelities exceeding 99.99%. This modest memory requirement could help reduce the footprint of the SFQ coprocessors and power dissipation while preserving their inherent advantages of scalability and cost-effectiveness.