Generating a 4-photon tetrahedron state: towards simultaneous super-sensitivity to non-commuting rotations
Generating a 4-photon tetrahedron state: towards simultaneous super-sensitivity to non-commuting rotations
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 ātetrahedron stateā, which is the optimal state for simultaneous estimation of all parameters describing a rotation.