Experimental Test of Local Hidden-Variable Theories

摘要: We have measured the linear polarization correlation between two photons from $7^{3}S_{1}\ensuremath{\rightarrow}6^{3}P_{1}\ensuremath{\rightarrow}6^{1}S_{0}$ cascade of ${\mathrm{Hg}}^{200}$. The results were used to evaluate Freedman's version Bell inequality, $\ensuremath{\delta}l~0$. Our result is ${\ensuremath{\delta}}_{\mathrm{exp}}=+0.046\ifmmode\pm\else\textpm\fi{}0.014$, in clear violation inequality and excellent agreement with quantum mechanical prediction, ${\ensuremath{\delta}}_{\mathrm{QM}}=+0.044\ifmmode\pm\else\textpm\fi{}0.007$. An important feature experiment was explicit measurement initial density matrix for cascading atoms.