Positive Maps Which Are Not Completely Positive
量子物理
2009-11-06 v1
摘要
The concept of the {\em half density matrix} is proposed. It unifies the quantum states which are described by density matrices and physical processes which are described by completely positive maps. With the help of the half-density-matrix representation of Hermitian linear map, we show that every positive map which is not completely positive is a {\em difference} of two completely positive maps. A necessary and sufficient condition for a positive map which is not completely positive is also presented, which is illustrated by some examples.
引用
@article{arxiv.quant-ph/0001053,
title = {Positive Maps Which Are Not Completely Positive},
author = {Sixia Yu},
journal= {arXiv preprint arXiv:quant-ph/0001053},
year = {2009}
}
备注
4pages,The Institute of Theoretical Physics, Academia Sinica, Beijing 100080, P.R. China