1207.2827 (Xiaofen Huang et al.)

Quantum entanglement and approximation by positive matrices    [PDF]

Xiaofen Huang, Naihuan Jing

We give an exact solution to the nonlinear optimization problem of approximating a Hermitian matrix by positive semi-definite matrices. Our algorithm was then used to judge whether a quantum state is entangled or not. We show that the exact approximation of a density matrices by tensor product of positive semi-definite operators is determined by the additivity property of the density matrix.

View original: http://arxiv.org/abs/1207.2827