# Experimental entanglement distillation and 'hidden' non-locality

 Authors: P G Kwiat, S Barraza-Lopez, A Stefanov, N Gisin Nature 409, 1014–1017 (2001) @@doi@@ Entangled states are central to quantum information processing, including quantum teleportation(1), efficient quantum computation(2) and quantum cryptography(3). In general, these applications work best with pure, maximally entangled quantum states. However, owing to dissipation and decoherence, practically available states are likely to be non-maximally entangled, partially mixed (that is, not pure), or both. To counter this problem, various schemes of entanglement distillation, state purification and concentration have been proposed(4-11). Here we demonstrate experimentally the distillation of maximally entangled states from non-maximally entangled inputs. Using partial polarizers, we perform a filtering process to maximize the entanglement of pure polarization-entangled photon pairs generated by spontaneous parametric down-conversion(12,13).(.) We have also applied our methods to initial states that are partially mixed. After filtering, the distilled states demonstrate certain non-local correlations, as evidenced by their violation of a form of Bell's inequality(14,15). Because the initial states do not have this property, they can be said to possess 'hidden' non-locality(6,16). distill.pdf

# BibTeX Source

@ARTICLE{Kwiat2001,
author = {Kwiat, P. G. and Barraza-Lopez, S. and Stefanov, A. and Gisin, N.},
title = {Experimental entanglement distillation and 'hidden' non-locality},
journal = {Nature},
year = {2001},
volume = {409},
pages = {1014--1017},
number = {6823},
abstract = {Entangled states are central to quantum information processing, including
quantum teleportation(1), efficient quantum computation(2) and quantum
cryptography(3). In general, these applications work best with pure,
maximally entangled quantum states. However, owing to dissipation
and decoherence, practically available states are likely to be non-maximally
entangled, partially mixed (that is, not pure), or both. To counter
this problem, various schemes of entanglement distillation, state
purification and concentration have been proposed(4-11). Here we
demonstrate experimentally the distillation of maximally entangled
states from non-maximally entangled inputs. Using partial polarizers,
we perform a filtering process to maximize the entanglement of pure
polarization-entangled photon pairs generated by spontaneous parametric
down-conversion(12,13).(.) We have also applied our methods to initial
states that are partially mixed. After filtering, the distilled states
demonstrate certain non-local correlations, as evidenced by their
violation of a form of Bell's inequality(14,15). Because the initial
states do not have this property, they can be said to possess 'hidden'
non-locality(6,16). },
owner = {cc},
sn = {0028-0836},
timestamp = {2010.08.20},
ut = {WOS:000167148800037}
}