  We present an analytical model for the theoretical analysis of spin dynamics
and spontaneous symmetry breaking in a spinor Bose-Einstein condensate (BEC).
This allows for an excellent intuitive understanding of the processes and
provides good quantitative agreement with experimental results in Phys. Rev.
Lett. 105, 135302 (2010). It is shown that the dynamics of a spinor BEC
initially prepared in an unstable Zeeman state mF=0 (|0>) can be understood by
approximating the effective trapping potential for the state |+-1> with a
cylindrical box potential. The resonances in the creation efficiency of these
atom pairs can be traced back to excitation modes of this confinement. The
understanding of these excitation modes allows for a detailed characterization
of the symmetry breaking mechanism, showing how a twofold spontaneous breaking
of spatial and spin symmetry can occur. In addition a detailed account of the
experimental methods for the preparation and analysis of spinor quantum gases
is given.
