Possibility of entanglement transfer in a uniform electric field

By using the Rashba Hamiltonian, the evolution of entanglement of two spin-12 charged particles in a homogeneous electric field is investigated. It is shown that Bell states become disentangled within finite time and there exist unentangled spin states that stay unentangled during evolution. The correlations among spin-spin, momentum-momentum, and spin-momentum entanglements are discussed in detail. Moreover, a state is constructed to illustrate the fact that spin-momentum entanglement is solely a dynamical effect that can arise without any entanglement of the other degree of freedom. The results are also extended to the mixed states where Werner states are treated.