Abstract:
Superconducting circuits are many-body systems of interacting electrons designed and fabricated in the form of electrical circuits and are playing a major role in the development of modern quantum technologies based on quantum information science. Collective excitation modes in the circuits are used as highly coherent superconducting qubits. With strong nonlinearity due to the Josephson effect and large dipole moments that allow fast control and readout of the quantum states, they are considered one of the most promising platforms for implementing quantum information processors. In addition, the qubits are coupled to resonators and waveguides to exploit the properties of those bosonic modes, either localized or propagating, as a versatile tool for microwave quantum optics and quantum sensing. The auxiliary modes can also be replaced with other collective modes found in solid-state physics, e.g., acoustic and magnetic ones, to form hybrid quantum systems, expanding the realm of quantum technologies.