Candidates for Universal Measures of Multipartite Entanglement

Abstract

We propose and examine several candidates for universal multipartite entanglement measures. The most promising candidate for applications needing entanglement in the full Hilbert space is the ent-concurrence, which detects all entanglement correlations while distinguishing between different types of distinctly multipartite entanglement, and simplifies to the concurrence for two-qubit mixed states. For applications where subsystems need internal entanglement, we develop the absolute ent-concurrence which detects the entanglement in the reduced states as well as the full state.

arXiv comment16 pages, 9 figures. v2: changed "nonlocal correlations" to "entanglement correlations" since that is what was meant and is more accurate since it distinguishes them from nonlocal correlations not involving entanglement. v3: incorporated new term "full k-partite entanglement" defined as "the absence of k-separability" for compatibility with existing terminology. No results affected