Many objects that we normally deal with in quantum physics are only visible with special microscopes—individual molecules or atoms, for example. However, the quantum objects that Elena Redchenko works with at the Institute for Atomic and Subatomic Physics at TU Wien can even be seen with the naked eye (with a little effort): They are hundreds of micrometers in size. Still tiny by human standards but gigantic in terms of quantum physics.

Those huge quantum objects are superconducting circuits —structures in which electric current flows at low temperatures without any resistance. In contrast to atoms, which have fixed properties, determined by nature, these artificial structures are extremely customizable and allow scientists to study different physical phenomena in a controlled manner. They can be seen as “artificial atoms,” whose physical properties can be adjusted at will.

By coupling them, a system was created that can be used to store and retrieve light—an important prerequisite for further quantum experiments. This experiment was carried out in the group of Johannes Fink at ISTA, with theoretical collaboration from Stefan Rotter at the Institute for Theoretical Physics at TU Wien. The results have now been published in the journal Physical Review Letters.