Comment on: Stochastic local operations and classical communication Invariant and the residual entanglement for n qubits

TL;DR

This paper critiques a recent definition of residual entanglement for n qubits, arguing it is not appropriate for odd numbers of qubits, highlighting limitations in the previous approach.

Contribution

The authors analyze the definition of residual entanglement for odd n qubits and demonstrate its inadequacy, proposing the need for a revised approach.

Findings

The residual entanglement definition fails for odd n qubits.

The critique reveals limitations in the existing measure.

A call for a new or modified residual entanglement measure.

Abstract

In a recent paper [Phys. Rev. A 76, 032304(2007)], Li et al. proposed the definition of the residual entanglement for n qubits by means of the Stochastic local operations and classical communication. Here we argue that their definition is not suitable for the case of odd-n qubits.