  We provide provide a detailed study of biasless coherent transport of singlet
electron pairs in one-dimensional (1D) channels induced by electron-electron
interactions that are time-varying in certain spatially localized regions of
the channel. When the time variation is cyclic, the mechanism is analogous to
the adiabatic quantum pumping of charge and spin previously studied. However,
the presence of interactions that vary only in localized regions of space
requires an intrinsically two-body description which is irreducible to the 1D
single particle scattering matrix elements that are sufficient to describe
quantum pumping of charge and spin. Here we derive a generalized theory for the
pumping of such interacting pairs starting from first principles. We show that
the standard description of charge pumping is contained within our more broadly
applicable expressions. We then apply our general results to a concrete lattice
model and obtain an exact analytical expression for the pumped singlet current.
We further demonstrate that such a model can be implemented with a chain of
currently available quantum dots with certain minor modifications that we
suggest; we present a detailed numerical feasibility analysis of the
characteristics of such experimentally realizable quantum dots, showing that
the requirements for a measurable pumped singlet current are within
experimental range.
