Energy relaxation of superconducting charge qubit via Andreev processes

Abstract

We study fundamental limitations on the energy relaxation rate of a superconducting charge qubit with a large-gap Cooper-pair box, ${\Delta }_b>{\Delta }_r$. At a sufficiently large mismatch between the gap energies in the box ${\Delta }_b$ and in the reservoir ${\Delta }_r$,"quasiparticle poisoning" becomes ineffective even in the presence of nonequilibrium quasiparticles in the reservoir. The qubit relaxation still may occur due to higher-order (Andreev) processes. In this paper we evaluate the qubit energy relaxation rate due to Andreev processes.

arXiv comment6 pages, 4 figures (accepted to Phys. Rev. B)

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Cited by in corpus (1)

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