When adiabatically varied in time, certain one-dimensional band insulators
allow for the quantized noiseless pumping of spin even in the presence of
strong spin orbit scattering. These spin pumps are closely related to the
quantum spin Hall system, and their properties are protected by a time-reversal
restriction on the pumping cycle. In this paper we study pumps formed of
one-dimensional insulators with a time-reversal restriction on the pumping
cycle and a bulk energy gap which arises due to interactions. We find that the
correlated gapped phase can lead to novel pumping properties. In particular,
systems with d different ground states can give rise to d+1 different
classes of spin pumps, including a trivial class which does not pump quantized
spin and d non-trivial classes allowing for the pumping of quantized spin
ℏ/n on average per cycle, where 1≤n≤d. We discuss an example
of a spin pump that transfers on average spin ℏ/2 without transferring
charge.Comment: 5 pages, 2 figure