Combinatorial entanglement

John Watrous

Zong‐Wen Yu, Su Hu, Chunlei Zhang

In this paper, we consider the problem of how to quantify entanglement for any multipartite quantum states. For bipartite pure states partial entropy is a good entanglement measure. By using partial entropy, we firstly introduce the Combinatorial Entropy of Fully entangled states (CEF) which can be used to quantify entanglement for any fully entangled pure states. In order to quantify entanglement for any multipartite states we also need another concept the Entanglement Combination (EC) which can be used to completely describe the entanglement between any parties of the given quantum states. Combining CEF with EC, we define the Combinatorial Entropy (CE) for any multipartite pure states and present some nice properties which indicate CE is a good entanglement measure. Finally, we point out the feasibility of extending these three concepts to mixed quantum states.

Samuel L. Braunstein, Sibasish Ghosh A, Simone Severini B

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.

Ingemar Bengtsson, Karol Życzkowski

Jeff Hecht

Joshua Lockhart, Otfried Gühne, Simone Severini B