Evaluation of entanglement measures by a single observable

Understand

We present observable lower bounds for several bipartite entanglement measures including entanglement of formation, geometric measure of entanglement, concurrence, convex-roof extended negativity, and G-concurrence.

• The lower bounds facilitate estimates of these entanglement measures for arbitrary finite-dimensional bipartite states.
• Moreover, these lower bounds can be calculated analytically from the expectation value of a single observable.
• Based on our results, we use several real experimental measurement data to get lower bounds of entanglement measures for these experimentally realized states.