Tools for Persistent-Current Qubits

Abstract : The project concentrates on the design, fabrication, implementation and operation of solids state quantum logical elements and circuits for the realization of quantum computers. It utilizes qubits based on circulating persistent currents in superconducting loops containing (three) Josephson junctions. This Final Report presents the major achievements obtained during the project, highlighting the progress from the initial spectroscopy and first Rabi results on a single qubit to the most recent finding of controlled quantum dynamics of multi- element circuits, controlled-invasiveness state detection, coupled 2-qubit systems, and large increase of coherence by proper circuit layout and parameter control. It briefly puts these into perspective with respect to the contribution of Persistent Current Qubits to the development of quantum information processing based on solid state devices.