Josephson Junction Materials Research Using Phase Qubits

Published

May 30, 2006

Author(s)

Raymond Simmonds, Dustin P. Hite, Robert McDermott, Matthias Steffen, Ken B. Cooper, Kristine Lang, John M. Martinis, David P. Pappas

Abstract

At present, the performance of superconducting qubits is limited by decoherence. Strong decoherence of phase qubits is associated with spurious microwave resonators residing within the Josephson junction tunnel barrier [1]. In this work, we investigate three different fabrication techniques for producing tunnel junctions, varying the properties of the superconductor-insulator interface, and through experimental measurements, we characterize the junction and corresponding qubit quality. We find that there is a strong correlation between the morphology of oxidized base electrodes and the lowering of subgap currents in the junction I-V characteristics, while there is no noticeable improvement in the performance of fabricated phase qubits. Thus, 'traditional' indicators of junction performance may not be enough to determine qubit performance. However, truly crystalline insulating barriers may be the key to improving Josephson junction based qubits.

Proceedings Title

Quantum Computation: solid state systems

Conference Dates

June 7-10, 2004

Conference Location

Naples, 1, IT

Conference Title

Macroscopic Quantum Coherence and Computing

Pub Type

Conferences

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Keywords

decoherence, Josephson tunnel junction, Materials research, Quantum computing

Citation

Simmonds, R. , Hite, D. , Mcdermott, R. , Steffen, M. , Cooper, K. , Lang, K. , Martinis, J. and Pappas, D. (2006), Josephson Junction Materials Research Using Phase Qubits, Quantum Computation: solid state systems, Naples, 1, IT, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=31821 (Accessed October 16, 2025)