Slowing and Storing Microwaves in a Single Superconducting Fluxonium Artificial Atom

TL;DR

This paper demonstrates Electromagnetically Induced Transparency (EIT), slow light, and photon storage using a single Fluxonium superconducting qubit in a microwave waveguide, advancing quantum memory and communication technologies.

Contribution

It introduces a novel EIT experiment with a single Fluxonium qubit, avoiding additional coupling elements, and showcases microwave photon storage and slow light in this system.

Findings

Observed EIT in a single Fluxonium qubit

Achieved 217 ns delay for slow light

Demonstrated microwave photon storage

Abstract

Three-level Lambda systems provide a versatile platform for quantum optical phenomena such as Electromagnetically Induced Transparency (EIT), slow light, and quantum memory. Such Lambda systems have been realized in several quantum hardware platforms including atomic systems, superconducting artificial atoms, and meta-structures. Previous experiments involving superconducting artificial atoms incorporated coupling to additional degrees of freedom, such as resonators or other superconducting atoms. In this work, we performed an EIT experiment in microwave frequency range utilizing a single Fluxonium qubit within a microwave waveguide. The Lambda system is consisted of two plasmon transitions in combination with one metastable state originating from the fluxon transition. In this configuration, the controlling and probing transitions are strongly coupled to the transmission line, safeguarding the transition between 0 and 1 states, and ensuring the Fluxonium qubit is close to the sweet spot. Our observations include the manifestation of EIT, a slowdown of light with a delay time of 217 ns, and photon storage. These results highlight the potential as a phase shifter or quantum memory for quantum communication in superconducting circuits.