The two-magnon-bound-state mass gap m2 for the two-dimensional quantum Ising model was investigated by means of the numerical diagonalization method; the low-lying spectrum is directly accessible via the numerical diagonalization method. It has been claimed that the ratio m2/m1 (m1: one-magnon...

We have studied the anisotropic two-dimensional nearest-neighbor Ising model with competitive interactions in both uniform longitudinal field H and transverse magnetic field Ω. Using the effective-field theory (EFT) with correlation in cluster with N=1 spin we calculate the thermodynamic...

In this paper, we investigate quantum correlations (QCs) and quantum phase transition (QPT) in the Ising model with Dzyaloshinskii–Moriya (DM) interaction by employing the quantum renormalization group method. The results show that some quantum correlation measures can effectively exhibit the...