The phase space of a particle on a group manifold can be split in left and
right sectors, in close analogy with the chiral sectors in Wess Zumino Witten
models. We perform a classical analysis of the sectors, and the geometric
quantization in the case of SU(2). The quadratic relation, classically
identifying SU(2) as the sphere S3, is replaced quantum mechanically by a
similar condition on non-commutative operators ('quantum sphere'). The
resulting quantum exchange algebra of the chiral group variables is quartic,
not quadratic. The fusion of the sectors leads to a Hilbert space that is
subtly different from the one obtained by a more direct (un--split)
quantization.Comment: 25p, LaTeX, KUL-TF-93/4