Experimental entanglement distillation and 'hidden' non-locality

Authors:P G Kwiat, S Barraza-Lopez, A Stefanov, N Gisin
Journal:Nature 409, 1014–1017 (2001)
DOI:@@doi@@
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).
File: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}
}