Correcting Distortion of Base-band Exchange Pulses in Quantum Dot Qubits

Repeatedly identical control waveforms are necessary for high fidelity qubit control. In triple-dot exchange-only spin qubits, full Bloch-sphere control is achieved via baseband voltage pulses alone. This makes them sensitive to the effects of pulse distortion extending from kHz to GHz frequencies. Here we present a technique to correct the known distortion of our arbitrary waveform generators. The application of this correction lead to a reduction of single qubit infidelity from 0.5% to 0.2% as measured by the “blind randomized benchmarking” protocol [1]. Additionally, we will cover an extension to this routine where we are able to estimate and potentially correct residual pulse distortion using coherent qubit control experiments.
[1] R. W. Andrews, et al. Nat Nanotechnol. 14, 747 (2019).