Measurable genuine tripartite entanglement of ($2\otimes 2\otimes n$)-dimensional quantum states via only two simultaneous copies

TL;DR

This paper presents a method to measure genuine tripartite entanglement in ($2 ext{×}2 ext{×}n$)-dimensional quantum states using only two copies, simplifying experimental requirements compared to previous approaches.

Contribution

It introduces a novel scheme for directly measuring the tripartite entanglement of certain quantum states with only two copies, reducing experimental complexity.

Findings

Exact measurement of tripartite entanglement with two copies.

Proposed lower bounds for practical experimental implementation.

Demonstration example for three-qubit states.

Abstract

Usually, the three-tangle of a tripartite pure state of qubits can be directly measured with the simultaneous preparation of a not-less-than-four-fold copy of the state. We show that the exact genuine tripartite entanglement for ($2\otimes2\otimes n$)-dimensional pure quantum states can be measured in a similar manner, provided that only two simultaneous copies of the state are available. Lower bounds are also proposed for more convenient experimental operations. As an example, a comprehensive demonstration of the scheme is provided for the three-tangle of a three-qubit state.