Is there a measure for entanglement of $n$-qubit system?

Question

I am working on a topic related to an $n$-qubit system. I should obtain the entanglement.

As I searched, I could not find any measure to obtain the entanglement of a mixed $n$-qubit system.

Is there such a measure for that purpose?

Answer 1

There are many measures of entanglement, such as

• quantum discord
• partial positive transpose
• positvity of coherent information
• concurrence, and more.