Joint quantum measurements with minimum uncertainty

Martin Ringbauer, Devon N. Biggerstaff, Matthew A. Broome, Alessandro Fedrizzi, Cyril Branciard, Andrew G. White

Published 2013-08-26, updated 2013-08-28Version 2

Quantum physics constrains the accuracy of joint measurements of incompatible observables. Here we test tight measurement-uncertainty relations using single photons. We implement two independent, idealized uncertainty-estimation methods, the 3-state method and the weak-measurement method, and adapt them to realistic experimental conditions. Exceptional quantum state fidelities of up to 0.99998(6) allow us to verge upon the fundamental limits of measurement uncertainty.