| Time：1141119 (Wed.) 14:20~16:20 Speaker：Prof.柯忠廷/ Ke, Chung-Ting 中央研究院物理研究所/Institute of Physics, Academia Sinica Title：Optimizing the Environment and Fabrication for High-Fidelity Superconducting Qubit Abstract： High-quality superconducting qubits are essential for realizing fault-tolerant quantum computation. Achieving such high performance requires not only a clean fabrication process but also an optimized measurement environment. To achieve this, we introduce a new fabrication flow with an ultra-clean qubit characterization environment, enabling long energy relaxation times (T1) up to 336 μs. We first demonstrate that optimizing the measurement environment is equally crucial for improving qubit performance. By reducing infrared radiation and enhancing electromagnetic shielding, the average T1 time of our QPU improves from 185 μs to 276 μs with high stability. Simultaneously, the qubit temperature decreases from 61 mK to 18 mK, accompanied by a reduction in quasiparticle density. In addition, we employed a genuine process that significantly reduces the area exposed to fabrication chemicals, thereby suppressing losses originating from two-level systems, particularly at the metal–substrate interface. Moreover, the fabrication method is inherently scalable, offering a promising pathway toward high-quality, large-scale quantum processing units (QPUs). Our results present a comprehensive approach to developing high-quality superconducting qubits, addressing both fabrication and environmental optimization to advance scalable quantum computing. Place：S101, Gongguan Campus, NTNU |
