Purcell-Engineered Hybrid Coupler for Leakage-Suppressed Robust CZ Gates
The research proposes a hybrid coupler combining coherent interaction engineering with leakage-selective dissipation for superconducting CZ gates. By integrating a nonlinear transmon coupler with a coupled Purcell-filter and notch-resonator, the architecture significantly reduces leakage compared to single couplers while maintaining high fidelity across various device parameters. This demonstrates that engineered dissipation is an effective design tool for robust quantum gates.