Eur. Phys. J. B (2017) 90: 49
https://doi.org/10.1140/epjb/e2017-80004-1

Regular Article

Entanglement in the linear-chain Heisenberg antiferromagnet Cu(C₄H₄N₂)(NO₃)₂

¹ Departament de Física, Universitat de les Illes Balears, 07122 Palma de Mallorca, Balearic Islands, Spain
² Computer Sciences Department, Faculty of Computers and Information, Mansoura University, Egypt and Scientific Research Group, Mansora, Egypt
³ Information Technology Department, Al-Zahra College for Women, P.O. Box 3365, Muscat, Oman
⁴ Department of Physics, Faculty of Science, Al Faisaliah Campus, King Abdulaziz University, Jeddah, Saudi Arabia

^a e-mail: jbv276@uib.es

Received: 3 January 2017
Published online: 15 March 2017

Abstract

Quantum correlations are generally impossible to address directly in bulk systems. Quantum measures extended only to a few number of parties can be discussed in practice. In the present work we study a cluster of spins belonging to a compound whose structure is that of a quantum magnet. We reproduce at a much smaller scale the experimental outcomes and then we study the role of quantum correlations there. A macroscopic entanglement witness has been introduced in order to reveal quantum correlations at nonzero temperatures. The critical point beyond which entanglement is zero is found at T_c = 15 K.