  We study a one-dimensional (1D) interacting electronic liquid coupled to a 1D
array of classical magnetic moments and to a superconductor. We show that at
low energy and temperature the magnetic moments and the electrons become
strongly entangled and that a magnetic spiral structure emerges without any
adjustable parameters. For strong enough coupling between the two, the 1D
electronic liquid is driven into a topological superconducting phase supporting
Majorana fermions without any fine-tuning of external parameters. Our analysis
applies at low enough temperature to a quantum wire in proximity of a
superconductor when the hyperfine interaction between electrons and nuclear
spins is taken into account or to a chain of magnetic adatoms adsorbed on a
superconducting surface.
