title: Geometry and dynamics in the Fresnel transforms of discrete systems.
abstract: Free propagation in continuous optical and mechanical systems is generated by the momentum-squared operator and results in a shear of the phase space plane along the position coordinate. We examine three discrete versions of the Fresnel transform in periodic systems through their Wigner function on a toroidal phase space. But since it is topologically impossible to continuously and globally shear a torus, we examine a fourth version of the Fresnel transform on a spherical phase space, in a model based on the Lie algebra of angular momentum, where the corresponding Fresnel transform wrings the sphere.
authors.affiliation: Instituto de Ciencias Físicas, Universidad nacional Autónoma de México, Morelos, México. bwolf@fis.unam.mx
authors.forename: Kurt Bernardo
authors.initials: KB
authors.lastname: Wolf
authors.forename: Guillermo
authors.initials: G
authors.lastname: Krötzsch