Speeding up qubit control with bipolar single-flux-quantum pulse sequences

Abstract

The development of quantum computers based on superconductors requires the improvement of the qubit state control approach aimed at the increase of the hardware energy efficiency. A promising solution to this problem is the use of superconducting digital circuits operating with single-flux-quantum (SFQ) pulses, moving the qubit control system into the cold chamber. However, the qubit gate time under SFQ control is still longer than under conventional microwave driving. Here we introduce the bipolar SFQ pulse control based on ternary pulse sequences. We also develop a robust optimization algorithm for finding a sequence structure that minimizes the leakage of the transmon qubit state from the computational subspace. We show that the appropriate sequence can be found for arbitrary system parameters from the practical range. The proposed bipolar SFQ control reduces a single qubit gate time by halve compared to nowadays unipolar SFQ technique, while maintaining the gate fidelity over 99.99%.

14 pages, 4 figures

References in corpus (9)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Charge insensitive qubit design derived from the Cooper pair box
• Simple pulses for elimination of leakage in weakly nonlinear qubits
• Quantum feedback control of a superconducting qubit: Persistent Rabi oscillations
• Analytic control methods for high fidelity unitary operations in a weakly nonlinear oscillator
• Beyond Moore's technologies: operation principles of a superconductor alternative
• Observation of a many-body-localized discrete time crystal with a programmable spin-based quantum simulator
• Advances in Quantum Deep Learning: An Overview
• Scaling up Superconducting Quantum Computers with Cryogenic RF-photonics