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Springer proceedings in physics

Method of Equilibrium Density Matrix, Anisotropy and Superconductivity, Energy Gap

Boris Volodumurovich Bondarev

Published Dec 14, 2015• 2 citations
Publisher
DOI
10.1007/978-3-319-26324-3_12

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The density of quasiparticles typically observed in superconducting qubits exceeds the value expected in equilibrium by many orders of magnitude. Can this out-of-equilibrium quasiparticle density still possess an energy distribution in equilibrium with the phonon bath? Here, we answer this question affirmatively by measuring the thermal activation of charge-parity switching in a transmon qubit with a difference in superconducting gap on the two sides of the Josephson junction. We then demonstrate how the gap asymmetry of the device can be exploited to manipulate its parity.