Eur. Phys. J. B 81, 419-424 (2011)
https://doi.org/10.1140/epjb/e2011-20280-1

Quantum correlations in the dimerized spin chain at zero and finite temperatures

¹ Department of Physics, Sanjiang College, Nanjing, 210012, P.R. China
² School of Physics Science and Technology, Yangzhou University, Yangzhou, 225002, P.R. China
³ Department of Electronic and Information Engineering, Yangzhou Polytechnic Institute, Yangzhou, 225002, P.R. China
⁴ Faculty of Mathematics and Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, P.R. China

Corresponding author: ^a jian_jun_jiang@yahoo.cn

Received: 10 April 2011
Published online: 15 June 2011

Abstract

By using the method of exact diagonalization, we investigate the quantum correlation measured by quantum discord of the dimerized spin chain at both zero and finite temperatures. The results disclose that the quantum discord is robust at any finite parameter α and temperature T, in contrast to entanglement which shows a sudden death when the parameter α or the temperature T reaches a critical point. At finite temperature, it is interesting to find that the quantum discord QD_{2i-1, 2i} can increase with temperature T no matter if the entanglement EoF_{2i-1, 2i} exists or not. The research on the relation between the quantum discord and the quantum phase transition in the dimerized spin chain indicates that the transition can be characterized by the first derivation of the quantum discord at zero and low temperatures.