From Quantum Optics to Non-Commutative Geometry : A Non-Commutative   Version of the Hopf Bundle, Veronese Mapping and Spin Representation
  In this paper we construct a non-commutative version of the Hopf bundle by making use of Jaynes-Commings model and so-called Quantum Diagonalization Method. The bundle has a kind of Dirac strings. However, they appear in only states containing the ground one (${\cal F}\times \{\ket{0}\} \cup \{\ket{0}\}\times {\cal F} \subset {\cal F}\times {\cal F}$) and don't appear in remaining excited states. This means that classical singularities are not universal in the process of non-commutativization.   Based on this construction we moreover give a non-commutative version of both the Veronese mapping which is the mapping from $\fukuso P^{1}$ to $\fukuso P^{n}$ with mapping degree $n$ and the spin representation of the group SU(2).   We also present some challenging problems concerning how classical (beautiful) properties can be extended to the non-commutative case. 
Kazuyuki Fujii (Yokohama City University)