Correcting quantum channels by measuring the environment (pp156-160)
         Patrick Hayden and Christopher King
          doi: https://doi.org/10.26421/QIC5.2-6
Abstracts: We propose an entanglement tensor to quantitatively compute the entanglement of a general pure multipartite quantum state. We compare the ensuing tensor with the concurrence for bipartite state and apply the tensor measure to some interesting examples of entangled three-qubit and four-qubit states. It is shown that in defining the degree of entanglement of a multi-partite state, one needs to make assumptions about the willingness of the parties to cooperate. For such states our tensor becomes a measure of generalized entanglement of assistance. We also discuss the degree of entanglement and the concurrence of assistance of two generic multi-qubit states.
Key words: quantum entanglement, multipartite state