Explicit product ensembles for separable quantum states

Rudiger Schack, Carlton M. Caves
2000 Journal of Modern Optics  
We present a general method for constructing pure-product-state representations for density operators of N quantum bits. If such a representation has nonnegative expansion coefficients, it provides an explicit separable ensemble for the density operator. We derive the condition for separability of a mixture of the Greenberger-Horne-Zeilinger state with the maximally mixed state. *
doi:10.1080/095003400148286 fatcat:eka6eckmknhdpgj5diq3kkigja