Exploring the Effect of Noise on Geometric Phases using Superconducting Qubits

  1. S. Berger,
  2. M. Pechal,
  3. A. A. Abdumalikov Jr.,
  4. C. Eichler,
  5. L. Steffen,
  6. A. Fedorov,
  7. A. Wallraff,
  8. and S. Filipp
We make use of a superconducting qubit to study the effects of noise on adiabatic geometric phases. The state of the system, an effective spin one-half particle, is adiabatically guided along a closed path in parameter space and thereby acquires a geometric phase. By introducing artificial fluctuations in the control parameters, we measure the geometric contribution to dephasing for a variety of noise powers and evolution times. Our results clearly show that only fluctuations which distort the path lead to geometric dephasing. In a direct comparison with the dynamic phase, which is path-independent, we observe that the adiabatic geometric phase is less affected by noise-induced dephasing. This observation directly points towards the potential of geometric phases for quantum gates or metrological applications.
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