In Gerhard Kirchmair's laboratory at the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences in Innsbruck, Austria, superconducting quantum bits are coupled to waveguides. When several of these quantum bits are incorporated into the waveguide, they interact with each other, resulting in so-called dark states. “These are entangled quantum states that are completely decoupled from the outside world,” explains Max Zanner, first author of the paper. “They are invisible, so to speak, which is why they are called dark states.” These states are of interest for quantum simulations or the processing of quantum information - corresponding proposals have been made several times in recent years. To date, however, it has not been possible to control and manipulate these dark states appropriately without breaking their invisibility. Now, the team led by Gerhard Kirchmair has developed a system with which the dark states of superconducting circuits in a microwave waveguide can be manipulated from the outside.
For more information see:
Coherent control of a multi-qubit dark state in waveguide quantum electrodynamics. Maximilian Zanner, Tuure Orell, Christian M. F. Schneider, Romain Albert, Stefan Oleschko, Mathieu L. Juan, Matti Silveri, and Gerhard Kirchmair. Nature Physics 2022
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 801110.
ESQ has received funding from the Austrian Federal Ministry of Education, Science and Research (BMBWF).