Measuring the temperature dependence of individual two-level systems by direct coherent control.

  title={Measuring the temperature dependence of individual two-level systems by direct coherent control.},
  author={J{\"u}rgen Lisenfeld and Clemens M{\"u}ller and Jared H. Cole and Pavel A. Bushev and Alexander V. Lukashenko and Alexander Shnirman and Alexey V. Ustinov},
  journal={Physical review letters},
  volume={105 23},
We demonstrate a new method to directly manipulate the state of individual two-level systems (TLSs) in phase qubits. It allows one to characterize the coherence properties of TLSs using standard microwave pulse sequences, while the qubit is used only for state readout. We apply this method to measure the temperature dependence of TLS coherence for the first time. The energy relaxation time T1 is found to decrease quadratically with temperature for the two TLSs studied in this work, while their… 

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