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Resolving the positions of defects in superconducting quantum bits

Bilmes, Alexander; Megrant, Anthony; Klimov, Paul; Weiss, Georg; Martinis, John M.; Ustinov, Alexey V.; Lisenfeld, Jürgen

Solid-state quantum coherent devices are quickly progressing. Superconducting circuits, for instance, have already been used to demonstrate prototype quantum processors comprising a few tens of quantum bits. This development also revealed that a major part of decoherence and energy loss in such devices originates from a bath of parasitic material defects. However, neither the microscopic structure of defects nor the mechanisms by which they emerge during sample fabrication are understood. Here, we present a technique to obtain information on locations of defects relative to the thin film edge of the qubit circuit. Resonance frequencies of defects are tuned by exposing the qubit sample to electric fields generated by electrodes surrounding the chip. By determining the defect’s coupling strength to each electrode and comparing it to a simulation of the field distribution, we obtain the probability at which location and at which interface the defect resides. This method is applicable to already existing samples of various qubit types, without further on-chip design changes. It provides a valuable tool for improving the material quality and nano-fabrication procedures towards more coherent quantum circuits.

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Verlagsausgabe §
DOI: 10.5445/IR/1000117700
Veröffentlicht am 14.08.2020
DOI: 10.1038/s41598-020-59749-y
Zitationen: 4
Zitationen: 5
Cover der Publikation
Zugehörige Institution(en) am KIT Physikalisches Institut (PHI)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 12.2020
Sprache Englisch
Identifikator ISSN: 2045-2322
KITopen-ID: 1000117700
Erschienen in Scientific reports
Verlag Nature Research
Band 10
Heft 1
Seiten Art. Nr.: 3090
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Gefördert vom Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg (MWK) im Rahmen des Open-Access-Förderprogramms "BW BigDIWA"
Vorab online veröffentlicht am 20.02.2020
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