Author:
Ferretti Hugo,Yilmaz Y. Batuhan,Bonsma-Fisher Kent,Goldberg Aaron Z.,Lupu-Gladstein Noah,Pang Arthur O. T.,Steinberg Aephraim M.
Abstract
A primary goal of quantum metrology is to understand the optimal way to measure multiple incompatible observables. Here, we report on the experimental demonstration and characterisation of a four-photon state, the “tetrahedron state”, which is the optimal state for simultaneous estimation of all parameters describing a rotation.