Simultaneous minimum-uncertainty measurement of discrete-valued   complementary observables
  We have made the first experimental demonstration of the simultaneous minimum uncertainty product between two complementary observables for a two-state system (a qubit). A partially entangled two-photon state was used to perform such measurements. Each of the photons carries (partial) information of the initial state thus leaving a room for measurements of two complementary observables on every member in an ensemble. 
Alexei Trifonov, Gunnar Bjork, Jonas Soderholm