Examining quantum correlations in the XY spin chain by local quantum uncertainty.

We study the thermal quantum correlations in terms of entanglement, quantum discord (QD) and local quantum uncertainty (LQU) in the XY spin chain, and analyze their capability in detecting the critical points of quantum phase transition. By considering the effects of the three-site interaction, site distance, system size and anisotropy parameter, we show that LQU is superior to QD in detecting the critical points. The advantages of LQU are not to be restricted to zero temperature, and it is possible to estimate the critical points at high temperature. Furthermore, the properties of LQU are very interesting and exhibit different quantum correlations which cannot be shown by entanglement and QD. [ABSTRACT FROM AUTHOR]