Comment on "Groverian Entanglement Measure and Evolution of Entanglement in Search Algorithm for n(= 3, 5)-Qubit Systems with Real Coefficients" (Volume 6, Number 4, August 2007), by Arti Chamoli and C. M. Bhandari

TL;DR

This paper critiques a previous work by highlighting errors in the analytic expressions for the Groverian Entanglement Measure, demonstrating that the original formulas can incorrectly assign zero entanglement to some entangled states.

Contribution

It identifies and explains errors in the existing formulas for the Groverian measure, providing clarification and correction for accurate entanglement quantification.

Findings

Original formulas can incorrectly give zero entanglement for some entangled states

Explicit example demonstrating the flaw in the previous formulas

Discussion of the technical mistake in the original paper

Abstract

We point out that the main results-the analytic expressions for the Groverian Measure of Entanglement, in the above mentioned paper are erroneous. The technical mistake of the paper is discussed. It is shown by an explicit example that the formula for calculating the Groverian measure yields G(|\psi>) = 0 for some entangled states.