Correlating decoherence in transmon qubits: Low frequency noise by single fluctuators

  1. Steffen Schlör,
  2. Jürgen Lisenfeld,
  3. Clemens Müller,
  4. Andre Schneider,
  5. David P. Pappas,
  6. Alexey V. Ustinov,
  7. and Martin Weides
We report on long-term measurements of a highly coherent, non-tunable transmon qubit, revealing low-frequency burst noise in coherence times and transition frequency. We achieve this through a simultaneous measurement of the qubits relaxation and dephasing rate as well as its resonance frequency and an analysis of their correlations. These yield information about the microscopic origin of the intrinsic decoherence mechanisms in Josephson qubits. Our data is consistent with a small number of microscopic two-level systems located at the edges of the superconducting film, which is further confirmed by a spectral noise analysis.

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