Coexistence of nonequilibrium density and equilibrium energy distribution of quasiparticles in a superconducting qubit

• URL: http://arxiv.org/abs/2302.12330v4
• Date: Mon, 11 Mar 2024 20:07:50 GMT
• Title: Coexistence of nonequilibrium density and equilibrium energy distribution of quasiparticles in a superconducting qubit
• Authors: Thomas Connolly, Pavel D. Kurilovich, Spencer Diamond, Heekun Nho, Charlotte G. L. B{\o}ttcher, Leonid I. Glazman, Valla Fatemi, Michel H. Devoret
• Abstract summary: density of quasiparticles typically observed in superconducting qubits exceeds the value expected in equilibrium by many orders of magnitude. We measure 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.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: 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.

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