Issue
EPL
Volume 87, Number 4, August 2009
Article Number 40008
Number of page(s) 5
Section General
DOI http://dx.doi.org/10.1209/0295-5075/87/40008
Published online 15 September 2009
EPL, 87 (2009) 40008
DOI: 10.1209/0295-5075/87/40008

Entanglement temperature in molecular magnets composed of $\mth{S}$-spin dimers

D. O. Soares-Pinto1, 2, A. M. Souza3, R. S. Sarthour2, I. S. Oliveira2, M. S. Reis4, P. Brandão4, 5, J. Rocha4, 5 and A. M. dos Santos6

1   Instituto de Física de São Carlos, Universidade de São Paulo - P.O. Box 369, 13560-970, São Carlos, SP, Brazil
2   Centro Brasileiro de Pesquisas Físicas - Rua Dr. Xavier Sigaud 150, 22290-180, Rio de Janeiro, Brazil
3   Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo Waterloo, Ontario, N2L 3G1, Canada
4   CICECO, Universidade de Aveiro - 3810-193, Aveiro, Portugal, EU
5   Departamento de Química, Universidade de Aveiro - 3810-193 Aveiro, Portugal, EU
6   NSSD, ORNL - Oak Ridge, TN 37831-6475, USA

diogo.osp@ursa.ifsc.usp.br

received 4 May 2009; accepted in final form 17 August 2009; published August 2009
published online 15 September 2009

Abstract
In the present work, we investigate the quantum thermal entanglement in molecular magnets composed of dimers of spin S, using an Entanglement Witness built from measurements of magnetic susceptibility. An entanglement temperature, Te, is then obtained for some values of spin S. From this, it is shown that Te is proportional to the intradimer exchange interaction J and that entanglement appears only for antiferromagnetic coupling. The results are compared to experiments carried on three isostructural materials: ${\rm KNaMSi}_{4}{\rm O}_{10}$ (M=Mn, Fe or Cu).

PACS
03.67.Mn - Entanglement measures, witnesses, and other characterizations.
75.50.Xx - Molecular magnets.
03.67.Bg - Entanglement production and manipulation.

© EPLA 2009