Spectator Leakage Elimination in CZ Gates via Tunable Coupler Interference on a Superconducting Quantum Processor

Fuente: arXiv
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Autori principali: Wang, Peng, Lu, Bin-Han, Wang, Tian-Le, Zhang, Sheng, Chen, Zhao-Yun, Zhang, Hai-Feng, Zhao, Ren-Ze, Yang, Xiao-Yan, Zhao, Ze-An, Zhang, Zhuo-Zhi, Song, Xiang-Xiang, Wu, Yu-Chun, Duan, Peng, Guo, Guo-Ping
Natura: Preprint
Pubblicazione: 2025
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author Wang, Peng
Lu, Bin-Han
Wang, Tian-Le
Zhang, Sheng
Chen, Zhao-Yun
Zhang, Hai-Feng
Zhao, Ren-Ze
Yang, Xiao-Yan
Zhao, Ze-An
Zhang, Zhuo-Zhi
Song, Xiang-Xiang
Wu, Yu-Chun
Duan, Peng
Guo, Guo-Ping
author_facet Wang, Peng
Lu, Bin-Han
Wang, Tian-Le
Zhang, Sheng
Chen, Zhao-Yun
Zhang, Hai-Feng
Zhao, Ren-Ze
Yang, Xiao-Yan
Zhao, Ze-An
Zhang, Zhuo-Zhi
Song, Xiang-Xiang
Wu, Yu-Chun
Duan, Peng
Guo, Guo-Ping
contents Spectator-induced leakage poses a fundamental challenge to scalable quantum computing, particularly as frequency collisions become unavoidable in multi-qubit processors. We introduce a leakage mitigation strategy based on dynamically reshaping the system Hamiltonian. Our technique utilizes a tunable coupler to enforce a block-diagonal structure on the effective Hamiltonian governing near-resonant spectator interactions, confining the gate dynamics to a two-dimensional invariant subspace and thus preventing leakage by construction. On a multi-qubit superconducting processor, we experimentally demonstrate that this dynamic control scheme suppresses leakage rates to the order of $10^{-4}$ across a wide near-resonant detuning range. The method also scales effectively with the number of spectators. With three simultaneous spectators, the total leakage remains below the threshold relevant for surface code error correction. This approach eases the tension between dense frequency packing and high-fidelity gate operation, establishing dynamic Hamiltonian engineering as an essential tool for advancing fault-tolerant quantum computing.
format Preprint
id arxiv_https___arxiv_org_abs_2507_14531
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spectator Leakage Elimination in CZ Gates via Tunable Coupler Interference on a Superconducting Quantum Processor
Wang, Peng
Lu, Bin-Han
Wang, Tian-Le
Zhang, Sheng
Chen, Zhao-Yun
Zhang, Hai-Feng
Zhao, Ren-Ze
Yang, Xiao-Yan
Zhao, Ze-An
Zhang, Zhuo-Zhi
Song, Xiang-Xiang
Wu, Yu-Chun
Duan, Peng
Guo, Guo-Ping
Quantum Physics
Spectator-induced leakage poses a fundamental challenge to scalable quantum computing, particularly as frequency collisions become unavoidable in multi-qubit processors. We introduce a leakage mitigation strategy based on dynamically reshaping the system Hamiltonian. Our technique utilizes a tunable coupler to enforce a block-diagonal structure on the effective Hamiltonian governing near-resonant spectator interactions, confining the gate dynamics to a two-dimensional invariant subspace and thus preventing leakage by construction. On a multi-qubit superconducting processor, we experimentally demonstrate that this dynamic control scheme suppresses leakage rates to the order of $10^{-4}$ across a wide near-resonant detuning range. The method also scales effectively with the number of spectators. With three simultaneous spectators, the total leakage remains below the threshold relevant for surface code error correction. This approach eases the tension between dense frequency packing and high-fidelity gate operation, establishing dynamic Hamiltonian engineering as an essential tool for advancing fault-tolerant quantum computing.
title Spectator Leakage Elimination in CZ Gates via Tunable Coupler Interference on a Superconducting Quantum Processor
topic Quantum Physics
url https://arxiv.org/abs/2507.14531