  Alkaline-earth(-like) ultracold atoms, trapped in optical lattices and in the
presence of an external gauge field, can stabilise Mott insulating phases
characterised by density and magnetic order. We show that this property can be
used to realise a topological fractional pump. Our analysis is based on a
many-body adiabatic expansion and on time-dependent matrix-product-states
numerical simulations. We characterise the pumping protocol by including both
finite-size and non-adiabatic corrections. For a specific form of atom-atom
interaction, we present an exactly-solvable model of a fractional pump.
Finally, the numerical simulations allow us to thoroughly study a realistic
setup amenable of an experimental realisation.
