Computable and operationally meaningful multipartite entanglement measures

TL;DR

This paper introduces a new family of multipartite entanglement measures called Concentratable Entanglements, which unify existing measures, are non-increasing under LOCC, have operational meaning, and can be efficiently estimated on quantum computers.

Contribution

The paper presents a general framework for multipartite entanglement measures, including a family called Concentratable Entanglements, with operational interpretation and efficient quantum estimation methods.

Findings

Recover well-known entanglement measures as special cases.

Prove measures do not increase under LOCC.

Show measures can be estimated via parallelized SWAP test on quantum computers.

Abstract

Multipartite entanglement is an essential resource for quantum communication, quantum computing, quantum sensing, and quantum networks. The utility of a quantum state, $|\psi\rangle$, for these applications is often directly related to the degree or type of entanglement present in $|\psi\rangle$. Therefore, efficiently quantifying and characterizing multipartite entanglement is of paramount importance. In this work, we introduce a family of multipartite entanglement measures, called Concentratable Entanglements. Several well-known entanglement measures are recovered as special cases of our family of measures, and hence we provide a general framework for quantifying multipartite entanglement. We prove that the entire family does not increase, on average, under Local Operations and Classical Communications. We also provide an operational meaning for these measures in terms of probabilistic concentration of entanglement into Bell pairs. Finally, we show that these quantities can be efficiently estimated on a quantum computer by implementing a parallelized SWAP test, opening up a research direction for measuring multipartite entanglement on quantum devices.