Abstract
We introduce a new entanglement measure based on optimal entanglement witness. First of all, we show that the entanglement measure satisfies some necessary properties, including zero entanglements for all separable states, convexity, continuity, invariance under local unitary operations and non-increase under local operations and classical communication(LOCC). More than that, we give a specific mathematical expression for the lower bound of this entanglement measure for any bipartite mixed states. We further improve the lower bound for 22 systems. Finally, we numerically simulate the lower bound of several types of specific quantum states.