Related papers: Flexible Readout and Unconditional Reset for Superconducting Multi-Qubit Processors with Tunable Purcell Filters

Flexible Readout and Unconditional Reset for Superconducting Multi-Qubit Processors with Tunable Purcell Filters

URL: http://arxiv.org/abs/2507.06988v2
Date: Thu, 17 Jul 2025 05:25:07 GMT
Title: Flexible Readout and Unconditional Reset for Superconducting Multi-Qubit Processors with Tunable Purcell Filters
Authors: Yong-Xi Xiao, Da'er Feng, Xu-Yang Gu, Gui-Han Liang, Ming-Chuan Wang, Zheng-Yu Peng, Bing-Jie Chen, Yu Yan, Zheng-Yang Mei, Si-Lu Zhao, Yi-Zhou Bu, Cheng-Lin Deng, Kai Yang, Ye Tian, Xiaohui Song, Dongning Zheng, Yu-Xiang Zhang, Yun-Hao Shi, Zhongcheng Xiang, Kai Xu, Heng Fan,
Abstract summary: We show a scalable architecture employing frequency-tunable nonlinear Purcell filters, enabling flexible readout and fast unconditional reset of superconducting qubits.<n>We achieve a readout fidelity of $99.3%$ without any quantum-limited amplifier, even with a small dispersive shift.<n>This architecture shows exceptional performance in qubit readout, reset, and protection, marking it as a promising hardware component for advancing fault-tolerant quantum computing systems.
Score: 13.38844783880794
License: http://creativecommons.org/licenses/by-nc-nd/4.0/
Abstract: Achieving high-fidelity qubit readout and reset while preserving qubit coherence is essential for quantum error correction and other advanced quantum algorithms. Here, we design and experimentally demonstrate a scalable architecture employing frequency-tunable nonlinear Purcell filters, enabling flexible readout and fast unconditional reset of multiple superconducting qubits. Our readout protocol dynamically adjusts the effective linewidth of the readout resonator through a tunable Purcell filter, optimizing the signal-to-noise ratio during measurement while suppressing photon noise during idle periods. We achieve a readout fidelity of $99.3\%$ without any quantum-limited amplifier, even with a small dispersive shift. Moreover, by leveraging a reset channel formed via the adjacent coupling between the filter and the coupler, we realize unconditional qubit reset of both leakage-induced $|2\rangle$ and $|1\rangle$ states within 200 ns and reset of the $|1\rangle$ state alone within 75 ns, with error rates $\leq 1\%$. The filter also mitigates both photon-induced dephasing and the Purcell effect, thereby preserving qubit coherence. This scalable Purcell filter architecture shows exceptional performance in qubit readout, reset, and protection, marking it as a promising hardware component for advancing fault-tolerant quantum computing systems.

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