Measuring and correcting nanosecond pulse distortions in quantum-dot spin qubits

TL;DR

This paper presents a method to measure and correct nanosecond pulse distortions in silicon quantum-dot spin qubits, improving control fidelity by applying digital pre-distortion based on impulse response extraction.

Contribution

It introduces a scalable, device-level technique using detuning-axis pulsed spectroscopy to characterize and correct pulse distortions in quantum-dot spin qubits.

Findings

Reduced pulse distortions on >1 ns timescales

Decreased frequency chirp in exchange oscillations

Enhanced control fidelity in silicon quantum dots

Abstract

Gate-defined semiconductor quantum dots utilize fast electrical control to manipulate spin and charge states of individual electrons. Electrical pulse distortions can limit control fidelities but are difficult to measure at the device level. Here, we use detuning-axis pulsed spectroscopy to characterize baseband pulse distortions in a silicon double quantum-dot. We extract the gate-voltage impulse response and apply a digital pre-distortion filter to eliminate pulse distortions on timescales longer than 1~ns. With the pre-distortion, we reduce the frequency chirp of coherent exchange oscillations in a singlet-triplet qubit. Our results suggest a scalable and tuning-efficient method for characterizing pulse distortions in quantum-dot spin qubits.