Characterizations of Dark and Bright states using Autler-Townes Splitting in Strongly Coupled Transmon Atoms

Raveendharan Sundaram^1*, Wei-Chen Chien¹, Chien‐Han Chen², Cen-Shawn Wu², Hiroshi Shimada³, Watson Kuo¹

¹Department of Physics, National Chung Hsing University, Taichung City, Taiwan
²Department of Physics, National Changhua University of Education, Changhua City, Taiwan
³Department of Engineering Science, University of Electro-Communications, Tokyo, Japan

* Presenter:Raveendharan Sundaram, email:ravee_s@hotmail.com

In this study, the super-radiant and sub-radiant behavior in collective modes of strongly coupled transmon atoms are experimentally studied using the circuit quantum electrodynamics setup. The transmission change of the collective modes near the degenerate point uncovers the protected state known as the ‘dark state’. Autler-Townes splitting (ATS) revealed the allowed and forbidden transitions to the higher excited states with distinct splitting conditions. Further, we also explored the bias dependence of the relaxation rates for the collective modes which are analyzed by transition matrix element calculations that perfectly matches with the experimental findings.

Keywords: Dark state, Strong coupling, Quantum Optics, circuit QED