Coherent states for a quantum particle on a circle
  The coherent states for the quantum particle on the circle are introduced. The Bargmann representation within the actual treatment provides the representation of the algebra $[\hat J,U]=U$, where $U$ is unitary, which is a direct consequence of the Heisenberg algebra $[\hat \phi, \hat J]=i$, but it is more adequate for the study of the circlular motion. 
K. Kowalski, J. Rembielinski and L.C. Papaloucas