  Topological states of interacting many-body systems are at the focus of
current research due to the exotic properties of their elementary excitations.
In this paper we suggest a realistic experimental setup for the realization of
a simple version of such a phase. We show how delta-interacting bosons hopping
on the links of a one-dimensional (1D) ladder can be used to simulate the
thin-torus-limit of the two-dimensional (2D) Hofstadter-Hubbard model at
one-quarter magnetic flux per plaquette. Bosons can be confined to ladders by
optical superlattices, and synthetic magnetic fields can be realized by far
off-resonant Raman beams. We show that twisted boundary conditions can be
implemented, enabling the realization of a fractionally quantized Thouless
pump. Using numerical density-matrix-renormalization-group (DMRG) calculations
we show that the groundstate of our model is an incompressible
symmetry-protected topological charge density wave (CDW) phase at average
filling $\rho = 1/8$ per lattice site, related to the 1/2 Laughlin-type state
of the corresponding 2D model.
