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arXiv · 1101.1341

Quasiparticle relaxation of superconducting qubits in the presence of flux

G. Catelani·Jens Koch·L. Frunzio·R. J. Schoelkopf·M. H. Devoret·L. I. Glazman
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Abstract

Quasiparticle tunneling across a Josephson junction sets a limit for the lifetime of a superconducting qubit state. We develop a general theory of the corresponding decay rate in a qubit controlled by a magnetic flux. The flux affects quasiparticles tunneling amplitudes, thus making the decay rate flux-dependent. The theory is applicable for an arbitrary quasiparticle distribution. It provides estimates for the rates in practically important quantum circuits and also offers a new way of measuring the phase-dependent admittance of a Josephson junction.

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G. Catelani, Jens Koch, L. Frunzio, R. J. Schoelkopf, M. H. Devoret, L. I. Glazman. 2011-01-21. Quasiparticle relaxation of superconducting qubits in the presence of flux. https://doi.org/10.1103/physrevlett.106.077002

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