Approaching the ultrastrong-coupling regime between an Andreev level and a microwave resonator

Uses a high-impedance NbTiN resonator coupled to an InAs–Al weak link to observe about 490 MHz pair-transition coupling and extract larger phase-dependent values approaching the ultrastrong-coupling regime.

Links

• Journal: Physical Review Applied
• Preprint: arXiv:2502.09243

Zoo Links

• andreev-pair-qubit