Estimation of the average of arbitrary unknown phase delays with Heisenberg-scaling precision
Danilo Triggiani, Vincenzo Tamma · Optical and Quantum Sensing and Precision Metrology II · 2022
We show an estimation scheme which reaches the Heisenberg-scaling sensitivity in the estimation of the average of the optical phases along the two arms of a Mach-Zehnder interferometer, by using a single squeezed vacuum state and homodyne detection at a single output port. We show that, in order to achieve this quantum advantage, it is required only a classical prior knowledge about the two phases, namely obtainable with a classical estimation strategy with shot-noise limited precision.