Entanglement and discord of the superposition of Greenberger-Horne-Zeilinger states

Preeti Parashar and Swapan Rana
Phys. Rev. A 83, 032301 – Published 2 March 2011

Abstract

We calculate the analytic expression for geometric measure of entanglement for arbitrary superposition of two N-qubit canonical orthonormal Greenberger-Horne-Zeilinger (GHZ) states and the same for two W states. In the course of characterizing all kinds of nonclassical correlations, an explicit formula for quantum discord (via relative entropy) for the former class of states has been presented. Contrary to the GHZ state, the closest separable state to the W state is not classical. Therefore, in this case, the discord is different from the relative entropy of entanglement. We conjecture that the discord for the N-qubit W state is log2N.

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  • Received 19 October 2010

DOI:https://doi.org/10.1103/PhysRevA.83.032301

©2011 American Physical Society

Authors & Affiliations

Preeti Parashar* and Swapan Rana

  • Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 BT Road, Kolkata, India

  • *parashar@isical.ac.in
  • swapanqic@gmail.com

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Issue

Vol. 83, Iss. 3 — March 2011

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