Logical multi-qubit entanglement with dual-rail superconducting qubits

Fuente: arXiv
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Main Authors: Huang, Wenhui, Sun, Xuandong, Zhang, Jiawei, Guo, Zechen, Huang, Peisheng, Liang, Yongqi, Liu, Yiting, Sun, Daxiong, Wang, Zilin, Xiong, Yuzhe, Yang, Xiaohan, Zhang, Jiajian, Zhang, Libo, Chu, Ji, Guo, Weijie, Jiang, Ji, Liu, Song, Niu, Jingjing, Qiu, Jiawei, Tao, Ziyu, Zhou, Yuxuan, Linpeng, Xiayu, Zhong, Youpeng, Yu, Dapeng
Format: Preprint
Published: 2025
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author Huang, Wenhui
Sun, Xuandong
Zhang, Jiawei
Guo, Zechen
Huang, Peisheng
Liang, Yongqi
Liu, Yiting
Sun, Daxiong
Wang, Zilin
Xiong, Yuzhe
Yang, Xiaohan
Zhang, Jiajian
Zhang, Libo
Chu, Ji
Guo, Weijie
Jiang, Ji
Liu, Song
Niu, Jingjing
Qiu, Jiawei
Tao, Ziyu
Zhou, Yuxuan
Linpeng, Xiayu
Zhong, Youpeng
Yu, Dapeng
author_facet Huang, Wenhui
Sun, Xuandong
Zhang, Jiawei
Guo, Zechen
Huang, Peisheng
Liang, Yongqi
Liu, Yiting
Sun, Daxiong
Wang, Zilin
Xiong, Yuzhe
Yang, Xiaohan
Zhang, Jiajian
Zhang, Libo
Chu, Ji
Guo, Weijie
Jiang, Ji
Liu, Song
Niu, Jingjing
Qiu, Jiawei
Tao, Ziyu
Zhou, Yuxuan
Linpeng, Xiayu
Zhong, Youpeng
Yu, Dapeng
contents Recent advances in quantum error correction (QEC) across hardware platforms have demonstrated operation near and beyond the fault-tolerance threshold, yet achieving exponential suppression of logical errors through code scaling remains a critical challenge. Erasure qubits, which enable hardware-level detection of dominant error types, offer a promising path toward resource-efficient QEC by exploiting error bias. Single erasure qubits with dual-rail encoding in superconducting cavities and transmons have demonstrated high coherence and low single-qubit gate errors with mid-circuit erasure detection, but the generation of multi-qubit entanglement--a fundamental requirement for quantum computation and error correction--has remained an outstanding milestone. Here, we demonstrate a superconducting processor integrating four dual-rail erasure qubits that achieves the logical multi-qubit entanglement with error-biased protection. Each dual-rail qubit, encoded in pairs of tunable transmons, preserves millisecond-scale coherence times and single-qubit gate errors at the level of $10^{-5}$. By engineering tunable couplings between logical qubits, we generate high-fidelity entangled states resilient to physical qubit noise, including logical Bell states (98.8% fidelity) and a three-logical-qubit Greenberger-Horne-Zeilinger (GHZ) state (93.5% fidelity). A universal gate set is realized through a calibrated logical controlled-NOT (CNOT) gate with 96.2% process fidelity, enabled by coupler-activated $XX$ interactions in the protected logical subspace. This work advances dual-rail architectures beyond single-qubit demonstrations, providing a blueprint for concatenated quantum error correction with erasure qubits.
format Preprint
id arxiv_https___arxiv_org_abs_2504_12099
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Logical multi-qubit entanglement with dual-rail superconducting qubits
Huang, Wenhui
Sun, Xuandong
Zhang, Jiawei
Guo, Zechen
Huang, Peisheng
Liang, Yongqi
Liu, Yiting
Sun, Daxiong
Wang, Zilin
Xiong, Yuzhe
Yang, Xiaohan
Zhang, Jiajian
Zhang, Libo
Chu, Ji
Guo, Weijie
Jiang, Ji
Liu, Song
Niu, Jingjing
Qiu, Jiawei
Tao, Ziyu
Zhou, Yuxuan
Linpeng, Xiayu
Zhong, Youpeng
Yu, Dapeng
Quantum Physics
Recent advances in quantum error correction (QEC) across hardware platforms have demonstrated operation near and beyond the fault-tolerance threshold, yet achieving exponential suppression of logical errors through code scaling remains a critical challenge. Erasure qubits, which enable hardware-level detection of dominant error types, offer a promising path toward resource-efficient QEC by exploiting error bias. Single erasure qubits with dual-rail encoding in superconducting cavities and transmons have demonstrated high coherence and low single-qubit gate errors with mid-circuit erasure detection, but the generation of multi-qubit entanglement--a fundamental requirement for quantum computation and error correction--has remained an outstanding milestone. Here, we demonstrate a superconducting processor integrating four dual-rail erasure qubits that achieves the logical multi-qubit entanglement with error-biased protection. Each dual-rail qubit, encoded in pairs of tunable transmons, preserves millisecond-scale coherence times and single-qubit gate errors at the level of $10^{-5}$. By engineering tunable couplings between logical qubits, we generate high-fidelity entangled states resilient to physical qubit noise, including logical Bell states (98.8% fidelity) and a three-logical-qubit Greenberger-Horne-Zeilinger (GHZ) state (93.5% fidelity). A universal gate set is realized through a calibrated logical controlled-NOT (CNOT) gate with 96.2% process fidelity, enabled by coupler-activated $XX$ interactions in the protected logical subspace. This work advances dual-rail architectures beyond single-qubit demonstrations, providing a blueprint for concatenated quantum error correction with erasure qubits.
title Logical multi-qubit entanglement with dual-rail superconducting qubits
topic Quantum Physics
url https://arxiv.org/abs/2504.12099