  The strongly correlated two-electron transport in one-dimensional channel
coupled with an Anderson-type impurity is solved exactly via a Bethe ansatz
approach. We show that the transport properties are fundamentally different for
spin singlet and triplet states, thus the impurity acts as a novel filter that
operates based on the total spin angular momentum of the electron pairs, but
not individual spins. The filter provides a deterministic generation of
electron entanglement in spin, as well as energy and momentum space.
