Purcell-Engineered Hybrid Coupler for Leakage-Suppressed Robust CZ Gates
Abstract
We propose a Purcell-engineered notch-filter hybrid coupler for superconducting controlled-Z (CZ) gates that combines coherent interaction engineering with leakage-selective dissipation. The architecture integrates a nonlinear transmon coupler with a coupled Purcell-filter and notch-resonator subsystem, providing additional control over both the coherent interaction pathways and the engineered dissipative environment. The filter branch reshapes the effective interaction pathways, while the notch resonator further tailors the frequency response of the coupled filter network and preserves strong leakage-selective dissipation. Using dressed-eigenstate analysis together with Lindblad master-equation simulations, we show that the proposed architecture substantially reduces leakage and retains high-fidelity, low-leakage operation compared with an optimized single-transmon coupler while remaining robust over a broad range of coherence assumptions and device parameters. The gate analysis reconstructs the projected computational quantum channel and therefore retains the phase information required to distinguish a CZ operation from identity. The nominal operating point occurs at tCZ=327.46 ns with FavgCZ=99.714%, Lavg=8.78×10−4, and Lmax=2.04×10−3. A minimax timing-robust operating point at 327.20 ns maintains FavgCZ≥99.590% over a ±0.50 ns timing window. These results demonstrate that engineered dissipation complements conventional coherent interaction engineering and provides an additional design degree of freedom for realizing robust, high-fidelity superconducting CZ gates.
Related
- Parametric DRAG for leakage-suppressed exchange gates in superconducting qubits
- Highly efficient hybrid white organic light-emitting diodes with suppressed efficiency roll-off based on dual triplet-management strategy
- User-in-the-loop adaptive mechanostimulation using structurally engineered hybrid piezoresistive force sensing
- Tunable, modeless, and hybridization-free cross-Kerr coupler for miniaturized superconducting qubits
- Ultra-compact 2 × 2 dual-mode power splitter based on a slotted subwavelength grating multimode interference coupler
BibTeX
@misc{wang2026purcellengineered,
title = {{Purcell-Engineered Hybrid Coupler for Leakage-Suppressed Robust CZ Gates}},
author = {Hui Wang and Feng Bao and Yan-Jun Zhao and Xun-Wei Xu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.23463},
eprint = {2607.23463},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.23463},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Purcell-Engineered Hybrid Coupler for Leakage-Suppressed Robust CZ Gates
AU - Hui Wang
AU - Feng Bao
AU - Yan-Jun Zhao
AU - Xun-Wei Xu
PY - 2026
DA - 2026/10/09
PB - arXiv
DO - 10.48550/arxiv.2607.23463
UR - https://arxiv.org/abs/2607.23463
AB - We propose a Purcell-engineered notch-filter hybrid coupler for superconducting controlled-Z (CZ) gates that combines coherent interaction engineering with leakage-selective dissipation. The architecture integrates a nonlinear transmon coupler with a coupled Purcell-filter and notch-resonator subsystem, providing additional control over both the coherent interaction pathways and the engineered dissipative environment. The filter branch reshapes the effective interaction pathways, while the notch resonator further tailors the frequency response of the coupled filter network and preserves strong leakage-selective dissipation. Using dressed-eigenstate analysis together with Lindblad master-equation simulations, we show that the proposed architecture substantially reduces leakage and retains high-fidelity, low-leakage operation compared with an optimized single-transmon coupler while remaining robust over a broad range of coherence assumptions and device parameters. The gate analysis reconstructs the projected computational quantum channel and therefore retains the phase information required to distinguish a CZ operation from identity. The nominal operating point occurs at t_CZ=327.46 ns with F_avg^CZ=99.714%, L_avg=8.78×10^−4, and L_max=2.04×10^−3. A minimax timing-robust operating point at 327.20 ns maintains F_avg^CZ≥99.590% over a ±0.50 ns timing window. These results demonstrate that engineered dissipation complements conventional coherent interaction engineering and provides an additional design degree of freedom for realizing robust, high-fidelity superconducting CZ gates.
ER -