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Quantum sensors for microscopic tunneling systems

Bilmes, Alexander 1; Volosheniuk, Serhii 1; Brehm, Jan David 1; Ustinov, Alexey V. 1; Lisenfeld, Jürgen 1
1 Karlsruher Institut für Technologie (KIT)


The anomalous low-temperature properties of glasses arise from intrinsic excitable entities, so-called tunneling Two-Level-Systems (TLS), whose microscopic nature has been baffling solid-state physicists for decades. TLS have become particularly important for micro-fabricated quantum devices such as superconducting qubits, where they are a major source of decoherence. Here, we present a method to characterize individual TLS in virtually arbitrary materials deposited as thin films. The material is used as the dielectric in a capacitor that shunts the Josephson junction of a superconducting qubit. In such a hybrid quantum system the qubit serves as an interface to detect and control individual TLS. We demonstrate spectroscopic measurements of TLS resonances, evaluate their coupling to applied strain and DC-electric fields, and find evidence of strong interaction between coherent TLS in the sample material. Our approach opens avenues for quantum material spectroscopy to investigate the structure of tunneling defects and to develop low-loss dielectrics that are urgently required for the advancement of superconducting quantum computers.

Verlagsausgabe §
DOI: 10.5445/IR/1000134473
Veröffentlicht am 28.06.2021
DOI: 10.1038/s41534-020-00359-x
Zitationen: 18
Zitationen: 22
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Experimentelle Teilchenphysik (ETP)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 12.2021
Sprache Englisch
Identifikator ISSN: 2056-6387
KITopen-ID: 1000134473
Erschienen in npj Quantum information
Verlag Nature Research
Band 7
Heft 1
Seiten Art.-Nr.: 27
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Vorab online veröffentlicht am 05.02.2021
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