The method for calculation of the correlation functions of the Ising-type systems with short-range interaction and with arbitrary value of spin is developed within cluster approximation. For the Ising model (spin
Sz=±1) the expressions for pair and ternary correlation functions within two-particle approximation in
{q}-space are obtained for the hypercubic Bravais lattices. In the 1D case the exact expressions for them in the site space is obtained as well. On the basis of the Glauber equation within two-particle cluster approximation the longitudinal dynamical susceptibility
χ({q},E) is found. In the 1D case and in the absence of external field the expression for
χ({q},E) is exact. For the Emery-Blume-Griffiths model (
Sz=−2,0,2) within two-particle approximation the pair correlation functions are calculated. The four-particle cluster approximation is used for calculation of static susceptibility
χ({q}) of
KD2PO4 ferroelectrics.
We study the peculiar dynamics of the Kitaev chain induced by nearest-neighbor (NN) interaction. We show that a strong NN interaction suppresses single-particle hopping but enhances pairing, resulting in a Wannier-Stark ladder. Based on the spin-fermion correspondence at the symmetry point, the model maps to a transverse field Ising model on a zigzag lattice, providing a clear physical picture and guiding experimental verification. The Wannier-Stark state corresponds to a localized domain wall between ferromagnetic and antiferromagnetic phases. It exhibits Bloch oscillation even in the absence of a longitudinal field, in contrast to previous works. Numerical simulations of time-dependent observables verify these conclusions. Our findings provide an example demonstrating emergent Stark many-body localization.
We study instantaneous quenches from infinite temperature to well below T_{c} in the two-dimensional square lattice Ising antiferromagnet in the presence of a longitudinal external magnetic field. Under single-spin-flip Metropolis algorithm Monte Carlo dynamics, this protocol produces a pair of magnetization plateaus that prevent the system from reaching the equilibrium ground state except for some special values of the field. We explain the plateaus in terms of local spin configurations that are stable under the dynamics.