Ultrastrong coupling regime of light-matter interaction using superinductor materials

by Alba Torras (IFAE)

Wednesday 24 May 2023, 13:00 → 14:00 Europe/Madrid

IFAE Seminar Room (IFAE)

Superconducting circuits offer a versatile platform to control and study light-matter interaction beyond the strong coupling regime. In this context, qubits play the role of artificial atoms, LC resonators act as cavities and the shared capacitance or inductance between elements define the degree of coupling. From a circuit design point of view, the coupling coefficient can be engineered to take values of the order of the bare frequencies of the qubit and the resonator (0.1 < g/ω < 1), allowing the study of the so-called ultrastrong coupling (USC) regime.
The challenge of obtaining large inductive couplings can be overcome by using superinductor materials showcasing large kinetic inductances such as granular aluminium.

In this study, we present an experimental qubit-resonator platform that incorporates superinductances as coupling elements. We will also show our parallel efforts investigating a novel superinducting material, nitridized aluminum (NitrAl), which may become an important qubit circuit element.