Measurable entanglement for tripartite quantum pure states of qubits

TL;DR

This paper demonstrates that all types of entanglement in tripartite qubit pure states, including those of reduced mixed states, can be experimentally measured using simple projective measurements on four copies, advancing quantum entanglement characterization.

Contribution

It introduces a method to measure all SLOCC entanglement classes in tripartite qubits using four copies and simple projective measurements, including mixed state entanglement.

Findings

All SLOCC entanglement types are measurable experimentally.

Entanglement of reduced mixed states can be exactly determined.

Concurrence of assistance can be measured with explicit physical equations.

Abstract

We show that for tripartite quantum pure states of qubits, all the kinds of entanglement in terms of SLOCC classification are experimentally measurable by simple projective measurements, provided that four copies of the composite quantum system are available. In particular, the entanglement of reduced density matrices, even though they are mixed states, can be exactly determined in experiment. Concurrence of assistance is also shown to be measurable by introducing an interesting equations with explicit physical meanings.