Tomographic transform on a sphere and topological insulators
  The tomographic transform was first introduced in the field theory literature long ago. It is closely related to Radon transform. In this paper we show how the tomographic transform can be implemented on a sphere and apply this result to study surface excitations of a spherical topological insulator with a single Dirac cone on the surface. 
N.M. Vildanov
cond-mat.mes-hall