1D J-J Ising model in 4 step modulated external magnetic field

Author: Giorgi Ichkitidze
Keywords: Ising model, phase transition
Annotation:

One-dimensional Ising model with competing interactions (ANNNI model) is considered, exhibiting antiferromagnetic next-nearest-neighbour coupling. Additionally, system is placed in a periodic external magnetic field. In the first part period of this field is assumed to be 2 times lattice spacing and quantum phase transitions are studied, meaning that phase diagram is determined at T=0K temperature. In the second part period of external magnetic field is assumed to be 4 times lattice spacing and transfer matrix is derived, which gives possibility to calculate thermodynamic quantities.