Directional parametric amplification with superconductor-insulator- superconductor junctions

In the quest of realizing a quantum computer, physicists are dealing with signals that can be as low as a single microwave photon. To detect such minute signals with quantum efficiencies sufficient to implement e.g. quantum error correction protocols, the signal must be amplified within the cryostat and the amplifier itself must be a quantum device. Developing these so-called quantum-limited amplifiers has been a very active research field in recent years. Yet current near quantum-limited amplifiers suffer from narrow amplification bandwidth or necessitate involved nanofabrication.

Our project aims at designing and building a quantum-limited amplifier with several GHz of bandwidth involving straightforward nanofabrication. This is made possible by a new approach theoretically proposed by Udson C. Mendes and co-workers from the CEA-Saclay and the Institut Quantique. It relies on the non-linearity of quasiparticle tunneling in the Josephson junction.

The development on an easy-to-build, broadband quantum-limited amplifier will have profound impact on the quantum information community and will likely lead to new projects and funding opportunities.