The Laplacian of a Graph as a Density Matrix: A Basic Combinatorial Approach to Separability of Mixed States
Samuel L. Braunstein, Sibasish Ghosh, Simone Severini · 2004
We study entanglement properties of mixed density matrices obtained from combinatorial laplacian matrices of graphs. We observe that some classes of graphs give arise to entangled (separable) states independently of their labelings.