Realization of dark state in a three-dimensional transmon superconducting qutrit
Yuhao Liu, Dong Lan, Xinsheng Tan, Jie Zhao, Peng Zhao, Mengmeng Li, Ke Zhang, Kunzhe Dai, Zhiyuan Li, Qiang Liu, Shudong Huang, Guangming Xue, Peng Xu, Haifeng Yu, Shi-Liang Zhu, Yang Yu · Applied Physics Letters · 2015
We realize the dark state in a three-dimensional transmon superconducting qutrit that consists of three cascading energy levels: |0⟩, |1⟩, and |2⟩. When the system is simultaneously driven with two tone microwaves on resonance with |0⟩, |1⟩ and |1⟩, |2⟩, respectively, it is found that the state of the system will generally evolve in time domain. However, the qutrit state is frozen-out if it is initialized in a dark state for corresponding drive amplitudes. We observe this freeze-out phenomenon by changing the amplitude of the microwaves while fixing the initial state or vice versa.