| Time：115/10/28 (Wed.) 14:20~16:20 Speaker：Prof.陳永富(Yung-Fu Chen) 國立中央大學物理學系/Department Of Physics, National Central University Title：Experimentally Validated Energy Participation Ratio Calculations for Superconducting Qubits Abstract： Improving qubit coherence is as crucial as scaling up qubit numbers for fault-tolerant quantum computing. In superconducting circuits, microscopic defects in materials and interfaces can behave as two-level systems (TLSs), causing dielectric loss and qubit energy relaxation. Beyond materials engineering, optimizing circuit geometry to reduce electric-field energy stored in lossy regions offers another route to improved coherence. In this talk, we present an accurate and efficient method for calculating energy participation ratios (EPRs), addressing mesh-convergence challenges in finite-element simulations while controlling computational costs. Measurements across qubit designs fabricated on the same wafers show that energy relaxation rates correlate with calculated EPRs, supporting the method’s validity. This approach enables systematic layout optimization and identifies material regions where improvements could most effectively enhance qubit coherence. Place：S101, Gongguan Campus, NTNU |
