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

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.

Updated acknowledgements, corrected typos

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Cited by in corpus (25)

• Resisting high-energy impact events through gap engineering in superconducting qubit arrays
• Phonon engineering of atomic-scale defects in superconducting quantum circuits
• Systematic study of High $E_J/E_C$ transmon qudits up to $d=12$
• Modeling phonon-mediated quasiparticle poisoning in superconducting qubit arrays
• Quasiparticle effects in magnetic-field-resilient 3D transmons
• Spin Environment of a Superconducting Qubit in High Magnetic Fields
• Observation of discrete charge states of a coherent two-level system in a superconducting qubit
• Spectral Signatures of Non-Trivial Topology in a Superconducting Circuit
• Andreev spin relaxation time in a shadow-evaporated InAs weak link
• An engineering guide to superconducting quantum circuit shielding
• Recovery dynamics of a gap-engineered transmon after a quasiparticle burst
• Nonequilibrium regimes for quasiparticles in superconducting qubits with gap-asymmetric junctions
• Quantum error mitigation in optimized circuits for particle-density correlations in real-time dynamics of the Schwinger model
• Low barrier ZrO${}_x$-based Josephson junctions
• Signatures of superconducting Higgs mode in irradiated Josephson junctions
• Charge Parity Rates in Transmon Qubits with Different Shunting Capacitors
• Theory of quasiparticle generation by microwave drives in superconducting qubits
• Systematic Schrieffer-Wolff-transformation approach to Josephson junctions: quasiparticle effects and Josephson harmonics
• Disentangling the Impact of Quasiparticles and Two-Level Systems on the Statistics of Superconducting Qubit Lifetime
• Generation of frequency-bin-encoded dual-rail cluster states via time-frequency multiplexing of microwave photonic qubits
• Nonequilibrium Quasiparticles in Superconducting Circuits: Energy Relaxation, Charge and Flux Noise
• Non-demolition fluorescence readout and high-fidelity unconditional reset of a fluxonium qubit via dissipation engineering
• AC Josephson Signatures of the Superconducting Higgs Mode
• Passive quantum error correction of photon loss at breakeven
• Quasiparticle-induced decoherence of a driven superconducting qubit