Projects per year
Abstract
We present here our recent results on qubit reset scheme based on a quantum-circuit refrigerator (QCR). In particular, we use the photon-assisted quasiparticle tunneling through a superconductor–insulator–normal-metal–insulator–superconductor junction to controllably decrease the energy relaxation time of the qubit during the QCR operation. In our experiment, we use a transmon qubit with dispersive readout. The QCR is capacitively coupled to the qubit through its normal-metal island. We employ rapid, square-shaped QCR control voltage pulses with durations in the range of 2–350 ns and a variety of amplitudes to optimize the reset time and fidelity. Consequently, we reach a qubit ground-state probability of roughly 97% with 80-ns pulses starting from the first excited state. The qubit state probability is extracted from averaged readout signal, where the calibration is based on Rabi oscillations, thus not distinguishing the residual thermal population of the qubit.
Original language | English |
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Article number | 234002 |
Number of pages | 8 |
Journal | Applied Physics Letters |
Volume | 121 |
Issue number | 23 |
DOIs | |
Publication status | Published - 7 Dec 2022 |
MoE publication type | A1 Journal article-refereed |
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ERC ConceptQ: New superconducting quantum-electric device concept utilizing increased anharmonicity, simple structure, and insensitivity to charge and flux noise
Möttönen, M., Vadimov, V., Mörstedt, T., Suominen, H. & Duda, R.
28/10/2022 → 31/10/2027
Project: EU: ERC grants
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Aalto: Quantum Technologies Industrial (Aalto)
01/11/2021 → 31/10/2024
Project: Business Finland: Strategic centres for science, technology and innovation (SHOK)
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SCAR: Scalable fabrication process for quantum-circuit refrigerators
Möttönen, M., Sah, A., Keränen, A., Mörstedt, T. & Ma, J.
22/12/2020 → 30/06/2022
Project: EU: ERC grants