Dielectric losses in multi-layer Josephson junction qubits

David Gunnarsson, J.-M. Pirkkalainen, J. Li, G.S. Paraoanu, P. Hakonen, M. Sillanpää, Mika Prunnila

Research output: Contribution to journalArticleScientificpeer-review

9 Citations (Scopus)

Abstract

We have measured the excited state lifetimes in Josephson junction phase and transmon qubits, all of which were fabricated with the same scalable multi-layer process. We have compared the lifetimes of phase qubits before and after removal of the isolating dielectric, SiNx, and find a fourfold improvement of the relaxation time after the removal. Together with the results from the transmon qubit and measurements on coplanar waveguide resonators, these measurements indicate that the lifetimes are limited by losses from the dielectric constituents of the qubits. We have extracted the individual loss contributions from the dielectrics in the tunnel junction barrier, AlOx, the isolating dielectric, SiNx, and the substrate, Si/SiO2, by weighting the total loss with the parts of the electric field over the different dielectric materials. Our results agree well with and complement the findings from other studies, demonstrating that superconducting qubits can be used as a reliable tool for high-frequency characterization of dielectric materials. We conclude with a discussion of how changes in design and material choice could improve qubit lifetimes by up to a factor of 4.
Original languageEnglish
Article number085010
JournalSuperconductor Science and Technology
Volume26
Issue number8
DOIs
Publication statusPublished - 2013
MoE publication typeA1 Journal article-refereed

Fingerprint

Dielectric losses
dielectric loss
Josephson junctions
life (durability)
Tunnel junctions
Coplanar waveguides
Excited states
tunnel junctions
complement
Relaxation time
Resonators
relaxation time
resonators
Electric fields
waveguides
electric fields
Substrates
excitation

Keywords

  • excited state lifetimes
  • high-frequency characterization
  • Josephson-junction
  • Josephson-Junction qubits
  • junction barrier
  • material choice
  • superconducting qubits
  • waveguide resonators

Cite this

Gunnarsson, D., Pirkkalainen, J-M., Li, J., Paraoanu, G. S., Hakonen, P., Sillanpää, M., & Prunnila, M. (2013). Dielectric losses in multi-layer Josephson junction qubits. Superconductor Science and Technology, 26(8), [085010]. https://doi.org/10.1088/0953-2048/26/8/085010
Gunnarsson, David ; Pirkkalainen, J.-M. ; Li, J. ; Paraoanu, G.S. ; Hakonen, P. ; Sillanpää, M. ; Prunnila, Mika. / Dielectric losses in multi-layer Josephson junction qubits. In: Superconductor Science and Technology. 2013 ; Vol. 26, No. 8.
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Gunnarsson, D, Pirkkalainen, J-M, Li, J, Paraoanu, GS, Hakonen, P, Sillanpää, M & Prunnila, M 2013, 'Dielectric losses in multi-layer Josephson junction qubits', Superconductor Science and Technology, vol. 26, no. 8, 085010. https://doi.org/10.1088/0953-2048/26/8/085010

Dielectric losses in multi-layer Josephson junction qubits. / Gunnarsson, David; Pirkkalainen, J.-M.; Li, J.; Paraoanu, G.S.; Hakonen, P.; Sillanpää, M.; Prunnila, Mika.

In: Superconductor Science and Technology, Vol. 26, No. 8, 085010, 2013.

Research output: Contribution to journalArticleScientificpeer-review

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T1 - Dielectric losses in multi-layer Josephson junction qubits

AU - Gunnarsson, David

AU - Pirkkalainen, J.-M.

AU - Li, J.

AU - Paraoanu, G.S.

AU - Hakonen, P.

AU - Sillanpää, M.

AU - Prunnila, Mika

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AB - We have measured the excited state lifetimes in Josephson junction phase and transmon qubits, all of which were fabricated with the same scalable multi-layer process. We have compared the lifetimes of phase qubits before and after removal of the isolating dielectric, SiNx, and find a fourfold improvement of the relaxation time after the removal. Together with the results from the transmon qubit and measurements on coplanar waveguide resonators, these measurements indicate that the lifetimes are limited by losses from the dielectric constituents of the qubits. We have extracted the individual loss contributions from the dielectrics in the tunnel junction barrier, AlOx, the isolating dielectric, SiNx, and the substrate, Si/SiO2, by weighting the total loss with the parts of the electric field over the different dielectric materials. Our results agree well with and complement the findings from other studies, demonstrating that superconducting qubits can be used as a reliable tool for high-frequency characterization of dielectric materials. We conclude with a discussion of how changes in design and material choice could improve qubit lifetimes by up to a factor of 4.

KW - excited state lifetimes

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Gunnarsson D, Pirkkalainen J-M, Li J, Paraoanu GS, Hakonen P, Sillanpää M et al. Dielectric losses in multi-layer Josephson junction qubits. Superconductor Science and Technology. 2013;26(8). 085010. https://doi.org/10.1088/0953-2048/26/8/085010