Two-electron entanglement in quasi-one-dimensional systems: Role of resonances

We analyze the role of resonances in two-fermion entanglement production for a quasi-one-dimensional two-channel scattering problem. We solve exactly for the problem of a two-fermion antisymmetric product state scattering off a double- δ -well potential. It is shown that the two-particle concurrence of the post-selected state has an oscillatory behavior where the concurrence vanishes at the values of momenta for virtual bound states in the double well. These concurrence zeros are interpreted in terms of the uncertainty in the knowledge of the state of the one-particle subspace-reduced one-particle density matrix. Our results suggest the manipulation of fermion entanglement production through the resonance structure of quantum dots.