Scaling superconducting quantum processors is increasingly constrained by the wiring, heat load, and calibration overhead associated with delivering high-resolution analog signals from room temperature to qubits at millikelvin temperature. Here we demonstrate a superconducting digital-to-analog converter (DAC) integrated with high-coherence fluxonium qubits in a multi-chip module architecture. The DACs generate persistent analog flux signals for tuning qubit parameters and are programmed deterministically using single-flux-quantum (SFQ) pulses, providing a digital interface compatible with established SFQ routing and demultiplexing technologies. Operating at millikelvin temperature, the DACs enable in-situ tuning of fluxonium qubits without measurable degradation of qubit coherence. The presented device provides a static control primitive for flux-tunable qubits, enabling parameter homogenization and eliminating the need for individual room-temperature DC bias lines. These results establish SFQ-programmable millikelvin DACs as a building block for digitally controlled superconducting quantum processors.
@article{arxiv.2604.25303,
title = {Millikelvin digital-to-analog converter for superconducting quantum processors},
author = {Ruizi Hu and Zongyuan Li and Zhancheng Yao and Yufei Wu and Qiang Zhang and Yining Jiao and Quan Guan and Lijing Jin and Wangwei Lan and Chengyao Li and Lu Ma and Liyong Mao and Huijuan Zhan and Ze Zhan and Ran Gao and Lijuan Hu and Kannan Lu and Xizheng Ma and Tenghui Wang and Peng Xiang and Chunqing Deng and Shasha Zhu},
journal= {arXiv preprint arXiv:2604.25303},
year = {2026}
}