  We establish a theoretical correspondence between spin-one antiferromagnetic
spinor condensates in an external magnetic field and quantum rotor models in an
external potential. We show that the rotor model provides a conceptually clear
picture of the possible phases and dynamical regimes of the antiferromagnetic
condensate. We also show that this mapping simplifies calculations of the
condensate's spectrum and wavefunctions. We use the rotor mapping to describe
the different dynamical regimes recently observed in $^{23}$Na condensates. We
also suggest a way to experimentally observe quantum mechanical effects
(collapse and revival) in spinor condensates.
