In situ mixer calibration for superconducting quantum circuits

TL;DR

This paper presents an in situ calibration method for superconducting quantum circuit mixers that improves control fidelity by using qubit responses, avoiding wiring modifications, and is validated through experimental benchmarking.

Contribution

The authors introduce a novel in situ calibration technique for superconducting mixers that leverages qubit responses, enhancing large-scale quantum control.

Findings

Improved single-qubit gate fidelity

Enhanced qubit coherence times

Effective calibration without wiring changes

Abstract

Mixers play a crucial role in superconducting quantum computing, primarily by facilitating frequency conversion of signals to enable precise control and readout of quantum states. However, imperfections, particularly carrier leakage and unwanted sideband signal, can significantly compromise control fidelity. To mitigate these defects, regular and precise mixer calibrations are indispensable, yet they pose a formidable challenge in large-scale quantum control. Here, we introduce an in situ calibration technique and outcome-focused mixer calibration scheme using superconducting qubits. Our method leverages the qubit's response to imperfect signals, allowing for calibration without modifying the wiring configuration. We experimentally validate the efficacy of this technique by benchmarking single-qubit gate fidelity and qubit coherence time.