Ferrotransmons and Ferrogatemons for Scalable Superconducting Quantum Computers

We propose alternative approaches to superconducting qubit technology. State-of-the-art implementations require flux-bias lines to tune the qubit frequency. These lines are controlled with currents which can damage qubit performance by inducing undesirable magnetic fields. This is detrimental to qubit performance and presents a severe bottleneck for scalability, as these lines are associated with significant heat dissipation. In this project, we advance two novel superconducting qubit designs capable of overcoming this challenge by eliminating the need for flux lines. This will involve the investigation of SIsFS junctions and their integration into quantum processors. One innovation track will implement SIsFS junctions in a transmon geometry—ferrotransmons. The other will hybridize gatemons and π-junction to deliver a ferrogatemon. Three of Europe’s leading quantum startups will integrate these alternative qubit types into prototype full-stack systems to test the implications of these novel approaches on scalability and performance quality. Scalable Quantum Computers Ferrotransmons and Ferrogatemons