Critical Point Estimation and Long-Range Behavior in the One-Dimensional XY Model Using Thermal Quan

We investigate the thermal quantum and total correlations in the one-dimensional anisotropic XY spin chain with transverse magnetic field. While we adopt concurrence and an easily observable version of geometric quantum discord to measure quantum correlations, we use measurement-induced nonlocality and an alternative quantity defined in terms of Wigner-Yanase information to quantify total correlations. We show that all of these measures are able to detect the critical point of the quantum phase transition at zero temperature. Moreover, we explore the ability of the measures to estimate the critical point at finite temperature, and show that their performance strongly depends on the anisotropy parameter of the Hamiltonian. Lastly, we study the effect of temperature on long-range correlations of the system.

[1] B. Çakmak, G. Karpat, and Z. Gedik, arXiv:1206.1019.