## A Note on Resistance of NPT to Mixture of Separable States    [PDF]

Bobo Hua, Xiu-Hong Gao, Ming-Jing Zhao, Shao-Ming Fei
We study the stability of NPT property of an arbitrary pure entangled state under the mixture of arbitrary pure separable states. For bipartite pure states with Schmidt number $n$ $(n>1)$ which is NPT, we show that this state is still NPT when it is mixed with no more than $\frac{n(n-1)}{2}-1$ arbitrary pure separable states. This result is generalized to multipartite case.
View original: http://arxiv.org/abs/1307.6657