Decoherence in a superconducting flux qubit with a pi-junction

T. Kato, T. Kato, Alexandre Avraamovitch Golubov, Y. Nakamura

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We consider the use of a pi junction for flux qubits to realize degenerate quantum levels without external magnetic field. On the basis of the Caldeira-Leggett model, we derive an effective spin-Boson model and study decoherence of this type of qubits. We estimate the dephasing time by using parameters from recent experiments of superconductor-insulator-ferromagnet-superconductor junctions and show that high critical current and large subgap resistance are required for the pi junction to realize a long coherent time.
Original languageUndefined
Pages (from-to)172502-
JournalPhysical review B: Condensed matter and materials physics
Issue number17
Publication statusPublished - 2007


  • METIS-242858
  • IR-58278

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