Three decades ago, Aharonov, Albert & Vaidman introduced a special protocol for quantum measurement, which they named Weak Measurements. As an extension of the standard von Neumann measurements scheme, this protocol leads to many surprising results, even though all these results are straight forward consequences of quantum mechanics. Many physicists have used the method of Weak Measurements to investigate a variety of topics, theoretically and experimentally. In this talk, I will discuss the practical application of this method to the specific task of precision measurement. We will see in which situations the method can be beneficial and how it can lead to another surprising result: using noise to improve the precision [1]. In addition, I will present an experiment applying this result for the task of measuring the Kerr non-linearity of a single photon, where we achieved a Heisenberg scaling of the precision [2].
[1] Using technical noise to increase the signal-to-noise ratio of measurements via imaginary weak values, YK, Phy. Rev. A 85 (6), 060102
[2] Heisenberg-scaling measurement of the single-photon Kerr non-linearity using mixed states, G Chen, N Aharon, YN Sun, ZH Zhang, WH Zhang, DY He, JS Tang, XY Xu, YK, CF Li, GC Guo, Nat. Comm. 9 (1), 93