Gated Conditional Displacement Readout of Superconducting Qubits

S. Touzard, A. Kou, N. E. Frattini, V. V. Sivak, S. Puri, A. Grimm, L. Frunzio, S. Shankar, M. H. Devoret

Research output: Contribution to journalArticlepeer-review


We have realized a new interaction between superconducting qubits and a readout cavity that results in the displacement of a coherent state in the cavity, conditioned on the state of the qubit. This conditional state, when it reaches the cavity-following, phase-sensitive amplifier, matches its measured observable, namely, the in phase quadrature. In a setup where several qubits are coupled to the same readout resonator, we show it is possible to measure the state of a target qubit with minimal dephasing of the other qubits. Our results suggest novel directions for faster readout of superconducting qubits and implementations of bosonic quantum error-correcting codes.

Original languageEnglish (US)
Article number080502
JournalPhysical review letters
Issue number8
StatePublished - Feb 25 2019
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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