Experimental entanglement distillation of two-qubit mixed states under local operations

We experimentally demonstrate optimal entanglement distillation from two forms of two-qubit mixed states under local filtering operations according to the constructive method introduced by Verstraete et al. ［Phys. Rev. A, 2001,64: 010101(R)］. In principle, our set-up can be easily applied to distil entanglement from arbitrary two-qubit partially mixed states. We also test the violation of the Clauser-Horne-Shimony-Holt inequality for the distilled state from the first form of mixed state to show its “hidden non-locality”.