Coherence dynamics of a photon-dressed qubit*

We consider a capacitively-shunted charge qubit in front of a mirror [1], affected by two signals: probe and dress signals. By varying the parameters of these signals and then analyzing the probe signal (reflected by the mirror) it is possible to explore the system properties. A similar system has been considered recently [1] but only a stationary picture was measured and described theoretically. The difference between the previous and the current configuration is in decreasing the qubit coupling to the environment, allowing to decrease the system decoherence time and perform time-domain measurements. We describe our system by solving both Bloch equations and rate equations. The obtained time-dependent occupation probabilities are related to the experimentally measured values. The study of this type of dynamics opens up new horizons for better understanding of the system properties and underlying physical processes such as Landau-Zener-Stückelberg-Majorana (LZSM) transitions.

 [1] “Landau-Zener-Stückelberg-Majorana interferometry of a superconducting qubit in front of a mirror”, P. Y. Wen, et al., PRB 102, 075448 (2020).