[10p-A24-1~15] 11.4 Junction and circuit fabrication process, digital applications

2:30 PM - 2:45 PM JST(5:30 AM - 5:45 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation Award

[10p-A24-3] kHz-Accuracy Transmon-Frequency Design Based on Impedance Evaluation across Josephson-Junction Ports

〇(D)Haruki Kikuchi^1,2, Kohei Matsuura¹, Shuhei Tamate³, Hiroto Mukai¹, Shinichi Inoue¹, Yasunobu Nakamura^1,3 (1.Tokyo Univ., 2.Fujitsu, 3.Riken)

Keywords:

superconducting qubit,Josephson harmonics

Toward kHz-accuracy frequency design of fixed-frequency transmons, we evaluated the environmental impedance across Josephson-junction ports using lumped-element models based on finite-element simulations. By incorporating the low-frequency self-resonant mode, the model accurately reproduced Ramsey spectra of highly excited levels and substantially reduced the fitting error. Furthermore, we showed that zero-point phase fluctuations of environmental modes impose a limitation on the unique estimation of the Josephson energy.