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Model of magnetic impurities within the Josephson junction of a phase qubita



David P. Pappas, R. P. Erickson


We consider a superconducting phase qubit consisting of a monocrystalline sapphire Josephson junction with symmetry axis perpendicular to the junction interfaces. Via the London gauge we present a theoretical model of Fe3+ magnetic impurities within the junction that describes the effect of a low concentration of impurities on the operation of a superconducting phase qubit. Specifically, we derive an interaction Hamiltonian expressed in terms of angular momentum states of the magnetic impurities and low-lying oscillator states of the qubit. We comment on the coherent coupling between qubit and magnetic impurities within the model, including the near-resonance behavior of qubit and Fe3+ electron states. 85.25.Dq,
Physical Review B (Condensed Matter and Materials Physics)


phase qubit, junction, impurity, two level system, tls
Created December 23, 2009, Updated February 19, 2017