MIRROR, MIRROR: Landau-Zener-Stückelberg-Majorana interferometry of a superconducting qubit in front of a mirror*

We investigate the Landau-Zener-Stückelberg-Majorana (LZSM) interferometry of a superconducting qubit in a semi-infinite transmission line terminated by a mirror. We tune the resonant frequency of the transmon-type qubit into a node of the electromagnetic (EM) field, “hiding” from the EM field. We modulate the resonant frequency of the qubit by applying a sinusoidal flux pump through on-chip flux line and performing spectroscopy by measuring the reflection coefficient of a weak probe in the system. Remarkable interference patterns emerge in the spectrum, which can be interpreted as multiphoton resonances in the dressed qubit. The multiphoton resonances are up to the fourth order. Our calculations agree well with the experiments.

[1] P. Y. Wen, B. Suri, O. V. Ivakhnenko, M. A. Nakonechnyi, S. N. Shevchenko, J.-J. Lin, W.-L. Lin, J. C. Chen, Franco Nori, I.-C. Hoi, Phys. Rev. B, 102, 075448 (2020)