Real-time frequency estimation of a qubit without single-shot-readout

Inbar Zohar, Ben Haylock, Yoav Romach, Muhammad Junaid Arshad, Nir Halay, Niv Druker, Rainer Stöhr, Andrej Denisenko, Yonatan Cohen, Cristian Bonato, Amit Finkler

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
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Quantum sensors can potentially achieve the Heisenberg limit of sensitivity over a large dynamic range using quantum algorithms. The adaptive phase estimation algorithm (PEA) is one example that was proven to achieve such high sensitivities with single-shot readout (SSR) sensors. However, using the adaptive PEA on a non-SSR sensor is not trivial due to the low contrast nature of the measurement. The standard approach to account for the averaged nature of the measurement in this PEA algorithm is to use a method based on `majority voting'. Although it is easy to implement, this method is more prone to mistakes due to noise in the measurement. To reduce these mistakes, a binomial distribution technique from a batch selection was recently shown theoretically to be superior, as all ranges of outcomes from an averaged measurement are considered. Here we apply, for the first time, real-time non-adaptive PEA on a non-SSR sensor with the binomial distribution approach. We compare the mean square error of the binomial distribution method to the majority-voting approach using the nitrogen-vacancy center in diamond at ambient conditions as a non-SSR sensor. Our results suggest that the binomial distribution approach achieves better accuracy with the same sensing times. To further shorten the sensing time, we propose an adaptive algorithm that controls the readout phase and, therefore, the measurement basis set. We show by numerical simulation that adding the adaptive protocol can further improve the accuracy in a future real-time experiment.
Original languageEnglish
Article number035017
JournalQuantum Science and Technology
Issue number3
Early online date10 May 2023
Publication statusPublished - Jul 2023


  • frequency estimation
  • magnetometry
  • quantum sensing
  • real time adaptive
  • single-shot readout
  • standard quantum limit
  • statistical inference


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