In microwave-based quantum circuits, including double quantum dots (DQDs), superconducting qubits and spin qubits, parametric amplifiers are indispensable in achieving high-fidelity qubit readouts. Despite its importance, the application of parametric amplifiers is hampered by several challenges, such as high insertion losses, constrained tunability, and a pronounced vulnerability to magnetic fields. Here, we demonstrate an on-site single-atom parametric amplifier (SAPA) within a reconfigurable quantum circuit, which consists of a superconducting microwave cavity and two GaAs gate-defined DQDs. Leveraging the inherent nonlinearity of the DQD, a parametric gain exceeding 11 dB is achieved. This gain contributes to enhance the qubit readout, as evidenced by exceeding two times improvement in the signal-to-noise ratio (SNR) when employing the DQD-based amplifier for reading out another DQD. Our work not only presents a versatile experimental platform with enhanced readout capabilities in quantum computing, but also introduces alternative choices of parametric amplifiers for a variety of microwave-based quantum circuits.
@article{arxiv.2603.18666,
title = {On-chip Parametric Amplification in a Double Quantum Dots Circuit},
author = {Yong-Qiang Xu and Rui Wu and Si-Si Gu and Shun-Li Jiang and Shu-Kun Ye and Bao-Chuan Wang and Hai-Ou Li and Guang-Can Guo and Chang-Ling Zou and Gang Cao and Guo-Ping Guo},
journal= {arXiv preprint arXiv:2603.18666},
year = {2026}
}