Mitigating state transition errors during readout with a synchronized flux pulse

Fuente: arXiv
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Main Authors: Li, Yulong, Nuerbolati, Wuerkaixi, Deng, Chunqing, Ma, Xizheng, Xiong, Haonan, Yu, Haifeng
Format: Preprint
Published: 2025
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_version_ 1866910252827410432
author Li, Yulong
Nuerbolati, Wuerkaixi
Deng, Chunqing
Ma, Xizheng
Xiong, Haonan
Yu, Haifeng
author_facet Li, Yulong
Nuerbolati, Wuerkaixi
Deng, Chunqing
Ma, Xizheng
Xiong, Haonan
Yu, Haifeng
contents State transitions during qubit measurements are extremely detrimental to quantum tasks that rely on repeated measurements, such as quantum error correction. These state transitions can occur when excessive measurement power leads to qubit excitations outside its computational space. Alternatively, the qubit state can decay rapidly when the measurement protocol inadvertently couples the qubit to lossy modes such as two-level systems (TLSs). We experimentally verify the impact of these TLSs in qubit readout by measuring the transition errors at different qubit flux bias. Because such state transitions during measurements are often localized in frequency space, we demonstrate the ability to avoid them during a fluxonium readout by exploiting the qubit's flux-tunability. By synchronizing the flux bias with the readout photon dynamics, we obtain an optimal readout fidelity of 99 % (98.4 %) in 1 us (0.5 us) integration time. Our work advances the understanding of state transitions in superconducting circuit measurements and demonstrates the potential of fluxonium qubits to achieve fast high-fidelity readout.
format Preprint
id arxiv_https___arxiv_org_abs_2507_14436
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mitigating state transition errors during readout with a synchronized flux pulse
Li, Yulong
Nuerbolati, Wuerkaixi
Deng, Chunqing
Ma, Xizheng
Xiong, Haonan
Yu, Haifeng
Quantum Physics
Applied Physics
State transitions during qubit measurements are extremely detrimental to quantum tasks that rely on repeated measurements, such as quantum error correction. These state transitions can occur when excessive measurement power leads to qubit excitations outside its computational space. Alternatively, the qubit state can decay rapidly when the measurement protocol inadvertently couples the qubit to lossy modes such as two-level systems (TLSs). We experimentally verify the impact of these TLSs in qubit readout by measuring the transition errors at different qubit flux bias. Because such state transitions during measurements are often localized in frequency space, we demonstrate the ability to avoid them during a fluxonium readout by exploiting the qubit's flux-tunability. By synchronizing the flux bias with the readout photon dynamics, we obtain an optimal readout fidelity of 99 % (98.4 %) in 1 us (0.5 us) integration time. Our work advances the understanding of state transitions in superconducting circuit measurements and demonstrates the potential of fluxonium qubits to achieve fast high-fidelity readout.
title Mitigating state transition errors during readout with a synchronized flux pulse
topic Quantum Physics
Applied Physics
url https://arxiv.org/abs/2507.14436