In recent years, notable progress has been made in the study of hole qubits in planar germanium, and circuit quantum electrodynamics (circuit QED) has emerged as a promising approach for achieving long-range coupling and scaling up of qubits. Here, we demonstrate the coupling between holes in a planar germanium double quantum dot (DQD) and photons in a microwave cavity. Specifically, a real-time calibrated virtual gate method is developed to characterize this hybrid system, which in turn allows us to determine the typical parameters sequentially through single-parameter fitting instead of conventional multi-parameter fitting with additional uncertainty, and gives the hole-photon coupling rate of g0/2π = 21.7 MHz. This work is a step toward further research on hole-photon interactions and long-range qubit coupling in planar germanium. The experimental method developed in this work contributes to the more accurate and efficient characterization of hybrid cavity-QED systems.
@article{arxiv.2310.08145,
title = {Coupling of hole double quantum dot in planar germanium to a microwave cavity},
author = {Yuan Kang and Zong-Hu Li and Zhen-Zhen Kong and Fang-Ge Li and Tian-Yue Hao and Ze-Cheng Wei and Song-Yan Deng and Bao-Chuan Wang and Hai-Ou Li and Gui-Lei Wang and Guang-Can Guo and Gang Cao and Guo-Ping Guo},
journal= {arXiv preprint arXiv:2310.08145},
year = {2024}
}