Polariton states in circuit QED for electromagnetically induced transparency

TL;DR

This paper demonstrates how electromagnetically induced transparency (EIT) can be achieved in superconducting circuit QED systems by engineering decay rates through a classical driving field, enabling control over polariton states.

Contribution

It introduces a method to realize EIT in circuit QED by using a driving field to create and manipulate polariton states, overcoming decay rate limitations.

Findings

EIT can be achieved in superconducting circuits via decay rate engineering.

Driving fields can create tunable polariton states in circuit QED.

EIT and Autler-Townes splitting are demonstrated in a three-level system.

Abstract

Electromagnetically induced transparency (EIT) has been extensively studied in various systems. However, it is not easy to observe in superconducting quantum circuits (SQCs), because the Rabi frequency of the strong controlling field corresponding to EIT is limited by the decay rates of the SQCs. Here, we show that EIT can be achieved by engineering decay rates in a superconducting circuit QED system through a classical driving field on the qubit. Without such a driving field, the superconducting qubit and the cavity field are approximately decoupled in the large detuning regime, and thus the eigenstates of the system are approximately product states of the cavity field and qubit states. However, the driving field can strongly mix these product states and so-called polariton states can be formed. The weights of the states for the qubit and cavity field in the polariton states can be tuned by the driving field, and thus the decay rates of the polariton states can be changed. We choose a three-level system with $\Lambda$-type transitions in such a driven circuit QED system, and demonstrate how EIT and ATS can be realized in this compound system. We believe that this study will be helpful for EIT experiments using SQCs.