Improvement of the polarized neutron interferometer setup demonstrating   violation of a Bell-like inequality
  For precise measurements with polarized neutrons high efficient spin-manipulation is required. We developed several neutron optical elements suitable for a new sophisticated setup, i.e., DC spin-turners and Larmor-accelerators which diminish thermal disturbances and depolarisation considerably. The gain in performance is exploited demonstrating violation of a Bell-like inequality for a spin-path entangled single-neutron state. The obtained value of S=2.365(13), which is much higher than previous measurements by neutron interferometry, is 28 $\sigma$ above the limit of S=2 predicted by contextual hidden variable theories. The new setup is more flexible referring to state preparation and analysis, therefore new, more precise measurements can be carried out. 
Hermann Geppert, Tobias Denkmayr, Stephan Sponar, Hartmut Lemmel and   Yuji Hasegawa
quant-ph