Optimal unambiguous comparison of two unknown squeezed vacua

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Authors	BUŽEK Vladimír OLIVARES Stefano SEDLÁK Michal RAPČAN Peter PARIS Matteo G. A.
Year of publication	2011
Type	Article in Periodical
Magazine / Source	Physical Review A
MU Faculty or unit	Faculty of Informatics
Citation
Web	http://arxiv.org/abs/1010.2937
Doi	http://dx.doi.org/10.1103/PhysRevA.83.012313
Field	Theoretical physics
Keywords	Quantum information processing; squeezed vacuum states; comparison
Description	We propose a scheme for unambiguous state comparison (USC) of two unknown squeezed vacuum states of an electromagnetic field. Our setup is based on linear optical elements and photon-number detectors, and achieves optimal USC in an ideal case of unit quantum efficiency. In realistic conditions, i.e., for non-unit quantum efficiency of photodetectors, we evaluate the probability of getting an ambiguous result as well as the reliability of the scheme, thus showing its robustness in comparison to previous proposals.
Related projects:	Highly Parallel and Distributed Computing Systems