Interacting defects generate stochastic fluctuations in superconducting qubits

Amorphous dielectric materials have been known to host two-level systems (TLSs) for more than four decades. Recent developments on superconducting resonators and qubits enable detailed studies on the physics of TLSs. In particular, measuring the loss of a device over long time periods (a few days) a...

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Bibliographic Details
Published in:Physical review. B 2021-09, Vol.104 (9), p.1, Article 094106
Main Authors: Béjanin, J. H., Earnest, C. T., Sharafeldin, A. S., Mariantoni, M.
Format: Article
Language:English
Subjects:
Amorphous materials
Dielectrics
Relaxation time
Simulation
Superconductivity
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Summary:Amorphous dielectric materials have been known to host two-level systems (TLSs) for more than four decades. Recent developments on superconducting resonators and qubits enable detailed studies on the physics of TLSs. In particular, measuring the loss of a device over long time periods (a few days) allows us to investigate stochastic fluctuations due to the interaction between TLSs. We measure the energy relaxation time of a frequency-tunable planar superconducting qubit over time and frequency. The experiments show a variety of stochastic patterns that we are able to explain by means of extensive simulations. The model used in our simulations assumes a qubit interacting with high-frequency TLSs, which, in turn, interact with thermally activated low-frequency TLSs. Our simulations match the experiments and suggest the density of low-frequency TLSs is about three orders of magnitude larger than that of high-frequency ones.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.104.094106