Optical implementation of spin squeezing

Takafumi Ono, Javier Sabines-Chesterking, Hugo Cable, Jeremy O'Brien, Jonathan Matthews

Research output: Contribution to journalArticle (Academic Journal)peer-review

8 Citations (Scopus)
357 Downloads (Pure)


Quantum metrology enables estimation of optical phase shifts with precision beyond the shot-noise limit. One way to exceed this limit is to use squeezed states, where the quantum noise of one observable is reduced at the expense of increased quantum noise for its complementary partner. Because shot-noise limits the phase sensitivity of all classical states, reduced noise in the average value for the observable being measured allows for improved phase sensitivity. However, additional phase sensitivity can be achieved using phase estimation strategies that account for the full distribution of measurement outcomes. Here we experimentally investigate a model of optical spin-squeezing, which uses post-selection and photon subtraction from the state generated using a parametric downconversion photon source, and we investigate the phase sensitivity of this model. The Fisher information for all photon-number outcomes shows it is possible to obtain a quantum advantage of 1.58 compared to the shot-noise value for five-photon events, even though due to experimental imperfection, the average noise for the relevant spin-observable does not achieve sub-shot-noise precision. Our demonstration implies improved performance of spin squeezing for applications to quantum metrology.
Original languageEnglish
Article number053005
Number of pages9
JournalNew Journal of Physics
Issue number5
Early online date16 May 2017
Publication statusPublished - May 2017

Structured keywords

  • Bristol Quantum Information Institute
  • QETLabs


  • Quantum Metrology
  • Optical phase measurement
  • Optical spin squeezing


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