Institut für Theorie der Kondensierten Materiem, Karlsruhe Institute of Technology (KIT)
sujet:Properties of coherent defects in superconducting qubits
Superconducting qubits often show signatures of coherent coupling to intrinsic two-level systems (TLS), which manifest themselves as avoided crossings in spectroscopic data. Near resonance with these TLS, the qubits dynamics will be strongly influenced. Since their coherence properties are often comparable or even superior to the qubit, one might even think of utilising the TLS. Unfortunately, their microscopic origin is not yet fully understood. I will give a summary of the joint theory-experiment efforts that have gone on in Karlsruhe over the last 2 years on the way towards a better understanding of these defects. Specifically, I will show a way to coherently manipulate individual TLS as well as a method to extract their properties from spectroscopic data and thus give constraints on the parameters of possible microscopic models.