Qubit Measurement by Multichannel Driving

Research output: Contribution to journalArticleScientificpeer-review


Research units

  • VTT Technical Research Centre of Finland


We theoretically propose and experimentally implement a method of measuring a qubit by driving it close to the frequency of a dispersively coupled bosonic mode. The separation of the bosonic states corresponding to different qubit states begins essentially immediately at maximum rate, leading to a speedup in the measurement protocol. Also the bosonic mode can be simultaneously driven to optimize measurement speed and fidelity. We experimentally test this measurement protocol using a superconducting qubit coupled to a resonator mode. For a certain measurement time, we observe that the conventional dispersive readout yields close to 100% higher average measurement error than our protocol. Finally, we use an additional resonator drive to leave the resonator state to vacuum if the qubit is in the ground state during the measurement protocol. This suggests that the proposed measurement technique may become useful in unconditionally resetting the resonator to a vacuum state after the measurement pulse.


Original languageEnglish
Article number080503
Pages (from-to)1-7
JournalPhysical Review Letters
Issue number8
Publication statusPublished - 25 Feb 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • Quantum measurement, Superconducting qubit, qubit readout, qubit dynamics

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