Checking the optimality of entanglement witnesses: an application to structural physical approximations
Checking the optimality of entanglement witnesses: an application to structural physical approximations
In 2008, the conjecture that structural physical approximations to optimal entanglement witnesses are separable states (in general unnormalized) was posed.In an attempt to disprove it, in (Ha K-C and Kye S-H, Separable states with unique decompositions, arXiv:1210.1088v3),Ha and Kye proposed a decomposable entanglement witness whose SPA is entangled and argued …