Superdiffusive comb: Application to experimental observation of anomalous diffusion in one dimension

A possible mechanism of superdiffusion of ultra-cold atoms in a one-dimensional polarization optical lattice, observed experimentally in [Phys. Rev. Lett. \textbf{108}, 093002 (2012)], is suggested. The analysis is based on a consideration of anomalous diffusion in a fractal comb [Phys. Rev. E \textbf{83}, 052106 (2011)]. It is shown that the transport exponent is determined by the fractal geometry of the comb due to recoil distributions resulting in L\'evy flights of atoms.