Research, Simulation, CAD, Fabrication and Measurement on Superconducting Quantum Computing Devices. Research on Tunable Coupler between superconducting transmon qubits.

𝗧𝗵𝗲𝘀𝗶𝘀: “𝘐𝘮𝘱𝘳𝘰𝘷𝘪𝘯𝘨 𝘙𝘦𝘢𝘥𝘰𝘶𝘵 𝘍𝘪𝘥𝘦𝘭𝘪𝘵𝘺 𝘷𝘪𝘢 𝘙𝘦𝘢𝘥𝘰𝘶𝘵 𝘖𝘱𝘵𝘪𝘮𝘪𝘻𝘢𝘵𝘪𝘰𝘯 𝘢𝘯𝘥 𝘈𝘤𝘵𝘪𝘷𝘦 𝘘𝘶𝘣𝘪𝘵 𝘙𝘦𝘴𝘦𝘵.” Researched on 𝗤𝘂𝗮𝗹𝗶𝘁𝘆 𝗙𝗮𝗰𝘁𝗼𝗿 𝗼𝗳 𝗥𝗲𝗮𝗱𝗼𝘂𝘁 𝗥𝗲𝘀𝗼𝗻𝗮𝘁𝗼𝗿𝘀: • 𝗟𝗮𝘆𝗼𝘂𝘁 𝗗𝗲𝘀𝗶𝗴𝗻 𝗮𝗻𝗱 𝗦𝗶𝗺𝘂𝗹𝗮𝘁𝗶𝗼𝗻: Designed the geometric structure of λ/4 transmission line resonators. Simulated resonance frequencies and load impedances using Ansys HFSS and AppCAD. • 𝗗𝗲𝘃𝗶𝗰𝗲 𝗙𝗮𝗯𝗿𝗶𝗰𝗮𝘁𝗶𝗼𝗻: Fabricated devices using established nano-fabrication techniques. • 𝗖𝗿𝘆𝗼𝗴𝗲𝗻𝗶𝗰 𝗠𝗲𝗮𝘀𝘂𝗿𝗲𝗺𝗲𝗻𝘁: Characterized device properties using the Low-Temperature Microwave Measurement System. • 𝗗𝗮𝘁𝗮 𝗔𝗻𝗮𝗹𝘆𝘀𝗶𝘀: Organized and analyzed datasets using Python packages and GitHub repository "𝘳𝘦𝘴𝘰𝘯𝘢𝘵𝘰𝘳_𝘵𝘰𝘰𝘭𝘴". Researched on 𝗦𝘂𝗽𝗲𝗿𝗰𝗼𝗻𝗱𝘂𝗰𝘁𝗶𝗻𝗴 𝗧𝗿𝗮𝗻𝘀𝗺𝗼𝗻 𝗤𝘂𝗯𝗶𝘁 𝗗𝗲𝘃𝗶𝗰𝗲: • 𝗥𝗲𝘀𝗼𝗻𝗮𝘁𝗼𝗿 𝗮𝗻𝗱 𝗤𝘂𝗯𝗶𝘁 𝗦𝗽𝗲𝗰𝘁𝗿𝗼𝘀𝗰𝗼𝗽𝘆: Measured frequency spectra of readout resonators and transmon qubits. Modulated readout pulse power to observe power dependence. Adjusted magnetic flux through the SQUID loop to observe flux dependence in resonators and qubits. • 𝗦𝗶𝗻𝗴𝗹𝗲 𝗤𝘂𝗯𝗶𝘁 𝗖𝗼𝗻𝘁𝗿𝗼𝗹: Fine-tuned π-pulse fidelity via Rabi and Ramsey experiments. Measured decoherence times with T1 and T2 tests. Assessed gate fidelity through single-qubit randomized benchmarking. • 𝗠𝘂𝗹𝘁𝗶𝗽𝗹𝗲 𝗤𝘂𝗯𝗶𝘁 𝗖𝗼𝗻𝘁𝗿𝗼𝗹: Performed two-qubit operations, including iSWAP and CZ gates, using qubit frequency modulation techniques. • 𝗥𝗲𝗮𝗱𝗼𝘂𝘁 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗮𝘁𝗶𝗼𝗻: Optimized readout fidelity by adjusting readout pulse power, frequency, and phase. Evaluated fidelity through single-shot experiments. • 𝗔𝗰𝘁𝗶𝘃𝗲 𝗤𝘂𝗯𝗶𝘁 𝗜𝗻𝗶𝘁𝗶𝗮𝗹𝗶𝘇𝗮𝘁𝗶𝗼𝗻: Developed and implemented active qubit reset techniques during the initialization stage of quantum algorithms to reduce time overhead and improve readout fidelity.

Participated in the establishment of the 𝗤𝘂𝗮𝗻𝘁𝘂𝗺 𝗠𝗮𝘁𝗲𝗿𝗶𝗮𝗹𝘀 𝗮𝗻𝗱 𝗗𝗲𝘃𝗶𝗰𝗲 𝗟𝗮𝗯𝗼𝗿𝗮𝘁𝗼𝗿𝘆 led by Prof. Chung-Ting Ke. Acquired proficiency in 𝗡𝗮𝗻𝗼-𝗙𝗮𝗯𝗿𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗧𝗲𝗰𝗵𝗻𝗶𝗾𝘂𝗲𝘀 through cleanroom training: • 𝗣𝗵𝘆𝘀𝗶𝗰𝗮𝗹 𝗩𝗮𝗽𝗼𝗿 𝗗𝗲𝗽𝗼𝘀𝗶𝘁𝗶𝗼𝗻: Thermal Evaporation, Electron-Beam Deposition, Sputter Deposition • 𝗟𝗶𝘁𝗵𝗼𝗴𝗿𝗮𝗽𝗵𝘆: Electron-Beam Writer, Laser Writer, Mask Aligner • 𝗠𝗮𝘁𝗲𝗿𝗶𝗮𝗹 𝗘𝘁𝗰𝗵𝗶𝗻𝗴: Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE), Wet Etching • 𝗦𝘂𝗿𝗳𝗮𝗰𝗲 𝗔𝗻𝗮𝗹𝘆𝘀𝗶𝘀: Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM), Focused Ion Beam (FIB) • 𝗣𝗿𝗼𝗽𝗲𝗿𝘁𝘆 𝗖𝗵𝗮𝗿𝗮𝗰𝘁𝗲𝗿𝗶𝘇𝗮𝘁𝗶𝗼𝗻: Wire Bonding, Physical Property Measurement System (PPMS) Developed and fabricated Niobium based 𝗝𝗼𝘀𝗲𝗽𝗵𝘀𝗼𝗻 𝗝𝘂𝗻𝗰𝘁𝗶𝗼𝗻 and Aluminum 𝗔𝗶𝗿-𝗕𝗿𝗶𝗱𝗴𝗲. Managed the installation of our 𝗕𝗼𝘁𝘁𝗼𝗺-𝗟𝗼𝗮𝗱𝗶𝗻𝗴 𝗙𝗮𝘀𝘁 𝗦𝗮𝗺𝗽𝗹𝗲 𝗘𝘅𝗰𝗵𝗮𝗻𝗴𝗲 𝗗𝗶𝗹𝘂𝘁𝗶𝗼𝗻 𝗥𝗲𝗳𝗿𝗶𝗴𝗲𝗿𝗮𝘁𝗼𝗿. Developed the 𝗟𝗼𝘄-𝗧𝗲𝗺𝗽𝗲𝗿𝗮𝘁𝘂𝗿𝗲 𝗠𝗶𝗰𝗿𝗼𝘄𝗮𝘃𝗲 𝗠𝗲𝗮𝘀𝘂𝗿𝗲𝗺𝗲𝗻𝘁 𝗦𝘆𝘀𝘁𝗲𝗺: • 𝗖𝗿𝘆𝗼𝗴𝗲𝗻𝗶𝗰 𝗖𝗼𝗺𝗽𝗼𝗻𝗲𝗻𝘁𝘀 𝗜𝗻𝘀𝘁𝗮𝗹𝗹𝗮𝘁𝗶𝗼𝗻: Installed components such as attenuators, frequency filters (infrared, band-pass, low-pass), circulators, isolators, directional couplers, bias-tees, traveling wave parametric amplifiers (TWPA), high electron mobility transistors (HEMT), room-temperature low-noise amplifiers. • 𝗖𝗼𝗹𝗱 𝗙𝗶𝗻𝗴𝗲𝗿 𝗗𝗲𝘀𝗶𝗴𝗻 𝗮𝗻𝗱 𝗙𝗮𝗯𝗿𝗶𝗰𝗮𝘁𝗶𝗼𝗻: Designed and fabricated an OFHC device holder, aluminum and μ-metal shielding, a 6-layer PCB, etc. Learned to utilize Computer-Aided Design programs such as KLayout, KQCircuit, FreeCAD, KiCAD. • 𝗜𝗺𝗽𝗹𝗲𝗺𝗲𝗻𝘁𝗮𝘁𝗶𝗼𝗻 𝗼𝗳 𝗠𝗲𝗮𝘀𝘂𝗿𝗲𝗺𝗲𝗻𝘁 𝗜𝗻𝘀𝘁𝗿𝘂𝗺𝗲𝗻𝘁𝘀: Integrated measurement instruments such as vector network analyzers (VNA), IQ mixers, Quantum Machines, QBlox.