Thermal quantum and classical correlations and entanglement in the $\mathit{XY}$ spin model with three-spin interaction

Thermal quantum and classical correlations and entanglement in the $XY$ spin model with three-spin interaction

Yan-Chao Li and Hai-Qing Lin

Phys. Rev. A 83, 052323 – Published 24 May 2011

Abstract

Pairwise quantum discord (QD) and classical correlation (CC) are studied in the $XY$ spin chain with three-spin interaction. We analyze their capability in detecting quantum phase transitions (QPTs) at both zero and finite temperatures and find that the pairwise QD of two neighboring spins is more reliable than that of any other distances in identifying QPTs. Both the QD and CC detect quantum critical points associated with first- and higher-order QPTs caused by field and three-spin interactions at finite temperatures. In addition, we find a different finite-size scaling behavior for QD from previous reports for the transverse field Ising case and show some interesting phenomena of QD and entanglement of formation for finite temperatures.