Superconducting qubit readout enhanced by path signature
Abstract
Quantum non-demolition measurement plays an essential role in quantum technology, crucial for quantum error correction, metrology, and sensing. Conventionally, the qubit state is classified from the raw or integrated time-domain measurement record. Here, we demonstrate a method to enhance the assignment fidelity of the readout by considering the "path signature" of this measurement record, where the path signature is a mathematical tool for analyzing stochastic time series. We evaluate this approach across five different hardware setups, including those with and without readout multiplexing and parametric amplifiers, and demonstrate a significant improvement in assignment fidelity across all setups. Moreover, we show that the path signature of the measurement record provides an expressive feature set that can be used to detect and classify state transitions that occurred during the measurement, improving the prediction of the qubit state at the end of the measurement. This method has the potential to become a foundational tool for quantum technology.
Cite
@article{arxiv.2402.09532,
title = {Superconducting qubit readout enhanced by path signature},
author = {Shuxiang Cao and Zhen Shao and Jian-Qing Zheng and Mohammed Alghadeer and Simone D Fasciati and Michele Piscitelli and Peter A Spring and Shiyu Wang and Shuhei Tamate and Neel Vora and Yilun Xu and Gang Huang and Kasra Nowrouzi and Yasunobu Nakamura and Irfan Siddiqi and Peter Leek and Terry Lyons and Mustafa Bakr},
journal= {arXiv preprint arXiv:2402.09532},
year = {2025}
}