Quasiparticle tunneling as a probe of Josephson junction barrier and capacitor material in superconducting qubits

نویسندگان

چکیده

Abstract Non-equilibrium quasiparticles are possible sources for decoherence in superconducting qubits because they can lead to energy decay or dephasing upon tunneling across Josephson junctions (JJs). Here, we investigate the impact of intrinsic properties two-dimensional transmon on quasiparticle (QPT) and discuss how use dynamics gain critical information about quality JJ barrier. We find rate non-equilibrium be sensitive choice shunting capacitor material their geometry qubits. In some devices, observe an anomalous temperature dependence QPT below 100 mK that deviates from a constant background associated with quasiparticles. speculate this behavior is caused by high transmission sites/defects within oxide barriers JJs, leading spatially localized subgap states. model assuming such defects generate regions smaller effective gap. Our results present unique situ characterization tool assess uniformity tunnel qubit shed light interact various elements circuit.

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ژورنال

عنوان ژورنال: npj Quantum Information

سال: 2022

ISSN: ['2056-6387']

DOI: https://doi.org/10.1038/s41534-022-00542-2