Entanglement measures and their properties in quantum field theory

Understand

An entanglement measure for a bipartite quantum system is a state functional that vanishes on separable states and that does not increase under separable (local) operations.

• It is well-known that for pure states, essentially all entanglement measures are equal to the v.
• Neumann entropy of the reduced state, but for mixed states, this uniqueness is lost.
• In quantum field theory, bipartite systems are associated with causally disjoint regions.