Nonlinear entanglement witnesses for four qubits in mutually unbiased bases
Abstract
Entanglement witness is a Hermitian operator that is useful for detecting the genuine multipartite entanglement of mixed states. Nonlinear entanglement witnesses have the advantage of a wider detection range in the entangled region. We construct genuine entanglement witnesses for four qubits density matrices in the mutually unbiased basis. First, we find the convex feasible region with positive partial transpose states. Then, to reveal the entangled regions, we present some appropriate linear entanglement witnesses and, we find the envelope of this family of linear witnesses as a nonlinear witness. Finally, we study thermal entanglement and we show for some Hamiltonians the witnesses can detect the entanglement at all temperatures.
Keywords
Cite
@article{arxiv.1507.06979,
title = {Nonlinear entanglement witnesses for four qubits in mutually unbiased bases},
author = {K. Aghayar and A. Heshmati and M. A. Jafarizadeh},
journal= {arXiv preprint arXiv:1507.06979},
year = {2020}
}
Comments
This is the last version before publication in "Journal of Statistical Mechanics: Theory and Experiment"