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FP5

SQUBIT-2 Informe resumido

Project ID: IST-2001-39083
Financiado con arreglo a: FP5-IST
País: Italy

Decoherence and1/f noise in Josephson qubits

We analysed the decoherence in Josephson Qubits in the charge regime induced by background charges in the substrate, which are also responsible for the 1/f noise. We proposed a microscopic model and study its dynamics pointing out the crucial role played by slow moving charges. Far away from the degeneracy we showed that this model for the dephasing can be solved exactly.

We also studied dynamical decoupling of a qubit from non-Gaussian quantum noise due to discrete sources, as bistable fluctuators and 1/f noise. We obtain analytic and numerical results for generic operating points. For very large pulse frequency, where dynamic decoupling compensates decoherence, we found universal behaviour. At intermediate frequencies noise can be compensated or enhanced, depending on the nature of the fluctuators and on the operating point.

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SCUOLA NORMALE SUPERIORE
PIAZZA DEI CAVALIERI 7
56126 PISA
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