  We show that strongly interacting multicomponent gases in one dimension
realize an effective spin chain, offering an alternative simple scenario for
the study of one-dimensional quantum magnetism in cold gases in the absence of
an optical lattice. The spin-chain model allows for an intuitive understanding
of recent experiments and for a simple calculation of relevant observables. We
analyze the adiabatic preparation of antiferromagnetic and ferromagnetic ground
states, and show that many-body spin states may be efficiently probed in
tunneling experiments. The spin-chain model is valid for more than two
components, opening the possibility of realizing SU(N) quantum magnetism in
strongly interacting one-dimensional alkaline-earth-metal or ytterbium Fermi
gases.
