Entanglement dynamics of electron spins in quantum dots under a nonuniform magnetic field

We investigate entanglement of two coupled electron spins in quantum dots (QDs) in the presence of an inhomogeneous magnetic field. The important effects of the inhomogeneous field are discussed for the dynamics of entanglement. Due to the system’s symmetry, the inhomogeneity of the field is shown not to affect the evolution of entanglement for Φ-type Bell state while it plays a key role for Ψ-type Bell state. For the maximal entangled Bell states, the field is positive for the entanglement dynamics. The mean field can increase the entanglement revival for Φ-type Bell state while an inhomogeneous field can promote the entanglement revival for Ψ-type Bell state. For the unentangled initial states, the field is destructive for the entanglement generation induced by the coupling of the two spins.