Correlators in simultaneous measurement of non-commuting qubit observables

ORAL

Abstract

We consider simultaneous continuous measurement of non-commuting qubit observables and analyze multi-time correlators $\langle i_{\kappa_1}(t_1)\cdots i_{\kappa_N}(t_N )\rangle$ for output signals $i_\kappa(t)$ from the detectors. Both informational ("spooky") and phase backactions from cQED-type measurements with phase-sensitive amplifiers are taken into account. We find an excellent agreement between analytical results and experimental data for two-time correlators of the output signals from simultaneous measurement of qubit observables $\sigma_x$ and $\sigma_\varphi = \sigma_x\cos\varphi + \sigma_y\sin\varphi$. The correlators can be used to extract small deviations of experimental parameters, e.g., phase backaction and residual Rabi frequency. The multi-time correlators are important in analysis of Bacon-Shor error correction/detection codes, operated with continuous measurements.

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Authors

  • Juan Atalaya

    University of California, Riverside

  • Shay Hacohen-Gourgy

    University of California, Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, CA 94720, USA., University of California, Berkeley, Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley CA 94720, USA., Quantum Nanoelectronics Laboratory,Department of Physics, University of California, Berkeley

  • Leigh Martin

    Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, CA 94720, USA., University of California, Berkeley, Quantum Nanoelectronics Laboratory,Department of Physics, University of California, Berkeley, Univ of California - Berkeley, Quantum Nanoelectronics Lab, Center for Quantum Coherent Sciences, UC Berkeley

  • Irfan Siddiqi

    Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley CA 94720, USA, Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, CA 94720, USA., Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley CA 94720, USA., University of California, Berkeley, Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA., Quantum Nanoelectronics Laboratory, Quantum Nanoelectronics Laboratory,Department of Physics, University of California, Berkeley, Quantum Nanoelectronics Lab, Center for Quantum Coherent Sciences, UC Berkeley

  • Alexander Korotkov

    University of California, Riverside, University of California at Riverside