Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 19: Superconductivity: Poster Session
TT 19.41: Poster
Montag, 7. März 2016, 15:00–18:00, Poster D
Dielectric susceptibility measurements of amorphous AlOx using superconducting resonators — •Saskia Meissner, Arnold Seiler, Hannes Rotzinger, and Georg Weiss — Physikalisches Institut, KIT Karlsruhe
The performance of superconducting circuits like Quantum Bits, SQUIDs and resonators is well known to be limited due to dielectric loss caused by tunneling systems (TS). They are a source of noise, energy loss and decoherence due to their coupling to electric fields.
Measurements of individual TS coherently coupled to a Josephson Junction (JJ) already indicate their broad energy distribution in the range of qubit frequencies.
Here we present measurements of the low temperature dielectric response of thin film AlOx in a wide frequency range in order to extract the spectral distribution of TS for a comparison with the standard tunneling model. AlOx films are fabricated in the same way as those of JJ implemented as plate capacitors. Direct capacitance measurements and selected resonances of lumped element superconducting resonators offer excitation frequencies from the kHz range up to the GHz range where superconducting quantum circuits are commonly operated.