Quantum Phase Transition and Thermal Entanglement in the Ising Model with Dzyaloshinskii-Moriya Interaction in an Inhomogeneous Magnetic Field

We investigate the quantum phase transition (QPT) and thermal entanglement in the two-qubit Ising model in an inhomogeneous magnetic field, and the DM interaction between the two lattices is considered. The results show the QPT highly relates to the magnetic intensity B and DM parameter D, by controlling the DM interaction D and external magnetic B we can change the positions of QPT points and the level spacing. Moreover, the QPT is closely related to thermal entanglement, when the QPT happens the ground state always changes between entanglement state and disentanglement state. The thermal entanglement highly depends on the system’s temperature T, DM intensity D and external magnetic field B. When T is lower, the entanglement can exhibit a platform-like region. By modulating the parameters D and B, the entanglement can be controlled and the entanglement switch can be realized.