# Electromagnetically induced transparency in circuit QED with nested polariton states

## TL;DR

This paper demonstrates electromagnetically induced transparency (EIT) in a circuit QED system with nested polariton states, revealing quantum interference effects and negative group velocities in a superconducting qubit setup.

## Contribution

It introduces a novel method to generate and observe EIT using nested polariton states in circuit QED, expanding the understanding of quantum interference in solid-state systems.

## Key findings

- EIT observed in a circuit QED system with nested polariton states
- Negative group velocities up to -0.52 km/s measured
- Verification of EIT using Akaike's information criterion

## Abstract

Electromagnetically induced transparency (EIT) is a signature of quantum interference in an atomic three-level system. By driving the dressed cavity-qubit states of a two-dimensional circuit QED system, we generate a set of polariton states in the nesting regime. The lowest three energy levels are utilized to form the $\Lambda$-type system. EIT is observed and verified by Akaike's information criterion based testing. Negative group velocities up to $-0.52\pm0.09$ km/s are obtained based on the dispersion relation in the EIT transmission spectrum.