Quantum entanglement, a fundamental property ensuring security of key distribution and efficiency of quantum computing, is extremely sensitive to decoherence. Different procedures have been developed in order to recover entanglement after propagation over a noisy channel. However, besides a certain amount of noise, entanglement is completely lost. In this case the channel is called entanglement breaking and any multi-copy distillation methods cannot help to restore even a bit of entanglement. We report the experimental realization of a new method which restores entanglement from a single photon entanglement breaking channel. The method based on measurement of environmental light and quantum feed-forward correction can reveal entanglement even if this one completely disappeared. This protocol provides new elements to overcome decoherence effects.
@article{arxiv.0804.3542,
title = {Experimental entanglement restoration on entanglement-breaking channels},
author = {Fabio Sciarrino and Eleonora Nagali and Francesco De Martini and Miroslav Gavenda and Radim Filip},
journal= {arXiv preprint arXiv:0804.3542},
year = {2008}
}