Completely positive covariant two-qubit quantum processes and optimal quantum NOT operations for entangled qubit pairs
Quantum Physics
2009-11-13 v1
Abstract
The structure of all completely positive quantum operations is investigated which transform pure two-qubit input states of a given degree of entanglement in a covariant way. Special cases thereof are quantum NOT operations which transform entangled pure two-qubit input states of a given degree of entanglement into orthogonal states in an optimal way. Based on our general analysis all covariant optimal two-qubit quantum NOT operations are determined. In particular, it is demonstrated that only in the case of maximally entangled input states these quantum NOT operations can be performed perfectly.
Cite
@article{arxiv.quant-ph/0603184,
title = {Completely positive covariant two-qubit quantum processes and optimal quantum NOT operations for entangled qubit pairs},
author = {J. Novotny and G. Alber and I. Jex},
journal= {arXiv preprint arXiv:quant-ph/0603184},
year = {2009}
}
Comments
14 pages, 2 figures