Coherent memory for microwave photons based on electromagnetically induced transparency in superconducting circuits

Yung-Fu Chen

Recent progresses in Josephson-junction-based superconducting circuits have propelled quantum information processing forward. To further develop an extensive quantum network on this platform, photonic quantum memory that can record flying qubit information is needed to assist in distributing entangled states among various nodes within the network. However, lacking a metastable state in most superconducting artificial atoms hinders developments in photonic quantum memory based on electromagnetically induced transparency (EIT). This presentation reports a superconducting qubit-resonator circuit setting up a three-level artificial atom: The frequency-tunable dressed qubit state and the high-coherence dressed resonator state establish the excited and metastable states, respectively. The parametric modulation of the qubit frequency bridges otherwise the first-order dipole-forbidden transition between the excited and metastable states. This artificial atom system, therefore, resembles a Λ-type atom and exhibits an EIT-like behavior. A probe pulse interacting with this artificial atom can be slowed down while applying parametric modulation. Furthermore, dynamic parametric modulation controls on this single atom realize on-demand coherent microwave storage and retrieval. These findings underscore the potential of our straightforward superconducting circuit design to attain photonic quantum memory in the microwave regime.