2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/114508The present methods for obtaining the optimal Lewenestein- Sanpera decomposition of a mixed state are difficult to handle analytically. We provide a simple analytical expression for the optimal Lewenstein-Sanpera decomposition by using semidefinite programming. Specially, we obtain the optimal Lewenstein-Sanpera decomposition for some examples such as: Bell decomposable state, Iso-concurrence state, generic two qubit state in Wootters's basis, $2\otimes 3$ Bell decomposable state, $d\otimes d$ Werner and isotropic states, a one parameter $3\otimes 3$ state and finally multi partite isotropic state.23 pagesQuantum PhysicsBest separable approximation with semi-definite programming methodtext