Eur. Phys. J. D (2016) 70: 149
https://doi.org/10.1140/epjd/e2016-70056-2

Regular Article

Identifying non-k-separability of a class of N-qubit complete graph states using correlation tensors

Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India

^a e-mail: velan@cnld.bdu.ac.in

Received: 29 January 2016
Received in final form: 20 May 2016
Published online: 5 July 2016

Abstract

We derive a general expression for standard tensor norm of N-body correlation tensors for N-qubit complete graph states. With the help of this expression, we formulate a separability criterion that identifies non-k-separability of a class of N-qubit complete graph states, including GHZ state. We illustrate the performance of our criterion by considering the N-qubit complete graph states added with colored product noise. We also demonstrate that few local measurement settings are sufficient to evaluate our criterion.