Hybrid quantum circuits combine different physical systems with the aim to harness their strengths and bring about new quantum technologies. Within the HYBRIDQCIRCUITS (Hybrid quantum electrical circuits) project, significant progress was achieved in the field of hybrid devices involving atoms, electron spins and microwave frequency waves. The EU grant has funded a new laboratory at the University of Oxford to explore how elements of atomic physics, quantum optics and condensed matter physics could be combined into a single circuit. The specialised equipment allowed scientists to conduct microwave experiments on quantum electrical circuits at very low temperatures. HYBRIDQCIRCUITS focused on microwave frequency waves and demonstrated their potential as elements of quantum circuits. These acoustic waves that travel along the surface of piezoelectric crystals have already been used in electronic devices, like resonators and filters. Such devices can easily be operated in the quantum regime. Moreover, they can be coupled to superconducting circuits. Another aspect explored was how to integrate carbon nanotubes in quantum electrical circuits. Carbon nanotubes are tubes of pure carbon just a few nanometres wide. Because they can carry electric currents like metal wires, these solid-state systems have been proposed as ready-made molecular-scale wires for building electronic circuitry. This initiative offered the basis for high-impact research in the growing field of quantum computing. Although thought to be an impossible technology because it harnesses the intricate power of quantum mechanics, this is an enabling technology coming closer and closer to real-life applications.
HYBRIDQCIRCUITS, quantum electrical circuits, superconducting circuits, carbon nanotubes