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arXiv · 2607.23681

Mitigation of Measurement-Induced State Transitions via a Fast-Load and Fast-Clear Readout

Wei-En Lin·Li-Chieh Hsiao·Chen-Hsun Ma·Erh-Hsiang Yeh·Wei-Lun Peng·Hsi-Sheng Goan·Cen-Shawn Wu·Yueh-Nan Chen·Yung-Fu Chen·Chung-Ting Ke·Chii-Dong Chen
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Abstract

High-fidelity and rapid qubit readout is essential for superconducting quantum processors, typically realized through the quantum non-demolition (QND) dispersive interaction within a qubit-resonator architecture. However, the achievable readout speed and fidelity are fundamentally limited by measurement-induced state transitions (MIST). For a transmon qubit, MIST is highly sensitive to the offset charge $n_g$ due to the charge dispersion of its higher-lying energy levels. In this work, we systematically investigate $n_g$-dependent MIST dynamics governed by the diabaticity and symmetry of pulse shaping within a charge-sensitive transmon architecture. We engineer fast-load and fast-clear pulses that effectively suppress resonator photon overshoots, thereby demonstrating a highly practical strategy to mitigate MIST without requiring complex waveforms or real-time feedback. Utilizing active gate-voltage control and rapid feedback, the measurement-induced transition probability is precisely mapped against $n_g$ and the steady-state resonator photon number, exhibiting strong agreement with numerical Floquet branch analysis. Ultimately, we evaluate the $n_g$-averaged total error probabilities for both readout and post-readout stages, verifying that a straightforward three-step pulse scheme consistently minimizes overall readout errors. Within the framework of large-scale superconducting quantum processors, this practical, hardware-free approach inherently offers a better trade-off between the readout signal-to-noise ratio and QND preservation.

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Wei-En Lin, Li-Chieh Hsiao, Chen-Hsun Ma, Erh-Hsiang Yeh, Wei-Lun Peng, Hsi-Sheng Goan, Cen-Shawn Wu, Yueh-Nan Chen, Yung-Fu Chen, Chung-Ting Ke, Chii-Dong Chen. 2026-07-26. Mitigation of Measurement-Induced State Transitions via a Fast-Load and Fast-Clear Readout. https://arxiv.org/abs/2607.23681

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