Clean and Tunable Phase Slip Qubit
Abstract
Quantum phase slips (QPS) is a fundamentally new physical phenomenon and can find a wide range of applications from metrology to building novel quantum computers. Previous work has demonstrated that the critical current of superconducting nanowires could be gated by external electric fields (aka "superconducting field effect"). The question of whether this effect can be used to produce QPS was a central question of our project. Although we have observed evidence of QPS, our results could not confirm the existence of QPS in electrically gated nanowires. This was the first direct test of the applicability of electrical gating for phase slips which will have an impact on the field and future experiments. We have developed a theoretical framework to design QPS qubits and several generations of chips were designed, fabricated and measured. The precursor of a qubit behavior was only observed for granular Al chips. However, the evidence of electric gating for nanowires has not been observed. We learned that Ti is not a preferred material for the fabrication neither for the readout resonator nor for QPS qubit possibly due to its prone to oxidation which likely increases losses at microwave frequencies. GrAl has been proven to be a promising material for the fabrication of QPS qubits. However, more efforts are needed to develop a reliable fabrication recipe.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 08, 2023
- Accession Number
- AD1216463
Entities
People
- Arkady Fedorov
Organizations
- Queensland University of Technology