par Cerf, Nicolas 
;Iblisdir, Sofyan
Référence Physical review. A, Atomic, Molecular, and Optical Physics, 64, page (032307)
Publication Publié, 2001
;Iblisdir, Sofyan Référence Physical review. A, Atomic, Molecular, and Optical Physics, 64, page (032307)
Publication Publié, 2001
Article révisé par les pairs
| Résumé : | The phase conjugation of an unknown Gaussian state cannot be realized perfectly by any physical process. A heuristic argument is used to derive a tight lower bound on the noise that must be introduced by an approximate phase conjugation operation. A universal transformation achieving the optimal imperfect phase conjugation is then presented, which is the continuous counterpart of the universal-NOT transformation for quantum bits. In addition, it is shown that more information can be encoded into a pair of conjugate Gaussian states than by using the same state twice. © 2001 The American Physical Society. |
