RESEARCH

We design, microfabricate and conduct cryogenic experiments with superconducting devices based on different circuit elements, from Josephson junctions to high kinetic inductance lines. We use these devices both for fundamental physics (e.g. cQED and mesoscopic physics) and application-oriented projects (e.g. quantum-limited read-out systems and quantum sensing).

Three platforms...

Josephson junctions The Josephson junction is the elementary building block that we exploit to build more advanced devices, such as superconducting qubits, superconducting parametric amplifiers and high-sensitivity quantum sensors. We are developing Josephson junctions based on Al/AlOx/Al stacks, exploiting vertical microfabrication processes. 

High kinetic inductance materials Kinetic inductance is a fundamental property of superconductors related to the inertia of the charge carriers in a AC field. We exploit kinetic inductance as a source of non-linearity to build circuits such as parametric amplifiers and tunable resonators as well as innovative devices like our microwave frequency shifter. We microfabricate high kinetic inductance circuits patterned in NbTiN, TiN and NbN thin films.

Hybrid systems Combining planar superconducting circuits with magnetomechanical elements allows to create hybrid systems that we exploit for fundamental physics experiments as well as sensing applications.

... to realise several devices, such as:

Josephson Parametric Amplifiers are resonant circuits that allow to amplify microwave signal with added noise at the quantum limit. We realise them by integrating a planar Al resonator with overlap Al/AlOx/Al Josephson junctions. Beside low-noise amplification, these circuits can be exploited for fundamental physics experiments in the fields of cQED and quantum optics.

Travelling Wave Parametric amplifiers (TWPAs) are based on non-linear effects achieved with arrays of Josephson junctions or disordered superconductors characterised by highly non-linear kinetic inductance. TWPAs are crucial to reach ultralow-noise amplification - potentially approaching the quantum noise limit - while ensuring a large bandwidh. We also exploit TWPAs for the generation of microwave entangled photons and microwave squeezing and to explore quantum fluids of light.

Tunable resonators are versatile circuits which can serve as platform for cQED and quantum optics experiments as well as quantum sensing applications. We are developing both Josephson-junctions-based and kinetic-inductance-based tunable resonators for a variety of projects. For example, we are working on Kinetic Inductance Current Sensors for multiplexed read-out of cryogenic sensors and we have demonstrated the generation synthetic dimensions and Bloch-wave dynamics in a frequency lattice.

Transmon qubits can be designed and microfabricated by combining high-Q planar aluminium resonators and Al/AlOx/Al Josephson junctions. We are interested in superconducting qubits mainly for quantum simulations and cQED experiments.

Main collaborators

The FBK SQ team is fruitfully collaborating 

• on a local level within the Quantum Community in Trento - Q@Tn, Physics Deparment at University of Trento, INFN-TIFPA, CNR Cryo Quantum Lab, CNR-BEC.

• on a national level with INFN, University of Milano Bicocca, INRiM, CNR, University of Padova

• on an international level, e.g. with Neel Institute, Grenoble (France), Aalto University (Finland), VTT (Finland), NIST (US), IMRE (Singapore), CERN (Switzerland), etc.