On the properties and controlling of thermal entanglement in a two-qubit Heisenberg XY model with external magnetic fields
外磁场下XY模型中两量子位热纠缠的性质及其调控研究

We investigate the thermal entanglement of Heisenberg-type coupled two-qubit system in the presence of two controllable magnetic fields (B+b) and (B-b). We find that under the condition of low temperature and uniform magnetic field, the entanglement between the two qubits exhibits platform-like behavior. By controlling the inhomogeneous magnetic field b and selecting suitable material we can optimize the thermal entanglement and enhance the critical temperature Tc of dead entanglement. We also find that the entanglement switch can be realized in a broader region of temperature by modulating the uniform field B.