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Decoherence in Josephson Qubits from Junction Resonances



Raymond Simmonds, Kristine Lang, Dustin Hite, David P. Pappas, John M. Martinis


We present experimental data that demonstrates a large reduction in the coherence of a Josephson phase qubit from spurious microwave resonances. These resonances are believed to arise from resonant fluctuators in the tunnel junction that couple to the junction critical current. We present a model that connects the subgap current-voltage characteristics with the magnitude of the rsonances, as well as the magnitude and density of 1/f critical-current fluctuations. This mechanism is argued to be a dominant source of decoherence in all present Josephson qubits. Improvements in the coherence of Josephson qubits will require materials research directed at reducing critical current fluctuations in tunnel junctions.
Physical Review Letters


1/f noise, decoherence, Josephson tunnel juntions, superconducting qubit


Simmonds, R. , Lang, K. , Hite, D. , Pappas, D. and Martinis, J. (2004), Decoherence in Josephson Qubits from Junction Resonances, Physical Review Letters, [online], (Accessed June 13, 2024)


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Created August 12, 2004, Updated October 12, 2021