Separable ellipsoids around multipartite states

Robin Y. Wen, Gilles Parez, Liuke Lyu +2

We show that, in finite dimensions, around any $m$-partite product state $\ddot{I}{}_{\mathrm{prod}}=\ddot{I}{}_1\otimes ...\otimes \ddot{I}{}_m$, there exists an ellipsoid of separable states centered around $Ï…