



02003nas a2200205   4500008004100000245008600041210006900127260001300196300001100209490000800220520132800228100002501556700002001581700003501601700002101636700002401657700002801681700002801709856006001737       2022                        eng d00aNegative Quasiprobabilities Enhance Phase Estimation in Quantum-Optics Experiment0 aNegative Quasiprobabilities Enhance Phase Estimation in QuantumO  c6/2/2022  a2205040 v1283 a<p>Operator noncommutation, a hallmark of quantum theory, limits measurement precision, according to uncertainty principles. Wielded correctly, though, noncommutation can boost precision. A recent foundational result relates a metrological advantage with negative quasiprobabilities&mdash;quantum extensions of probabilities&mdash;engendered by noncommuting operators. We crystallize the relationship in an equation that we prove theoretically and observe experimentally. Our proof-of-principle optical experiment features a filtering technique that we term partially postselected amplification (PPA). Using PPA, we measure a wave plate&rsquo;s birefringent phase. PPA amplifies, by over two orders of magnitude, the information obtained about the phase per detected photon. In principle, PPA can boost the information obtained from the average filtered photon by an arbitrarily large factor. The filter&rsquo;s amplification of systematic errors, we find, bounds the theoretically unlimited advantage in practice. PPA can facilitate any phase measurement and mitigates challenges that scale with trial number, such as proportional noise and detector saturation. By quantifying PPA&rsquo;s metrological advantage with quasiprobabilities, we reveal deep connections between quantum foundations and precision measurement.</p>1 aLupu-Gladstein, Noah1 aYilmaz, Batuhan1 aArvidsson-Shukur, David, R. M.1 aBrodutch, Aharon1 aPang, Arthur, O. T.1 aSteinberg, Aephraim, M.1 aHalpern, Nicole, Yunger  uhttps://link.aps.org/doi/10.1103/PhysRevLett.128.220504