Experimental investigation of the stronger uncertainty relations for all   incompatible observables
  The Heisenberg-Robertson uncertainty relation quantitatively expresses the impossibility of jointly sharp preparation of incompatible observables. However it does not capture the concept of incompatible observables because it can be trivial even for two incompatible observables. We experimentally demonstrate the new stronger uncertainty relations proposed by Maccone and Pati [Phys. Rev. Lett. 113, 260401 (2014)] relating on that sum of variances are valid in a state-dependent manner and the lower bound is guaranteed to be nontrivial for two observables being incompatible on the state of the system being measured. The behaviour we find agrees with the predictions of quantum theory and obeys the new uncertainty relations even for the special states which trivialize Heisenberg-Robertson relation. We realize a direct measurement model and give the first experimental investigation of the strengthened relations. 
Kunkun Wang, Xiang Zhan, Zhihao Bian, Jian Li, Yongsheng Zhang, and   Peng Xue
quant-ph