Superfluidity and collective oscillations of trapped Bose-Einstein   condensates in a periodical potential
  Based on a unified theoretical treatment of the 1D Bogoliubov-de Genes equations, the superfluidity phenomenon of the Bose-Einstein condensates (BEC) loaded into trapped optical lattice is studied. Within the perturbation regime, an all-analytical framework is presented enabling a straightforward phenomenological mapping of the collective excitation and oscillation character of a trapped BEC where the available experimental configurations also fit. 
C. Trallero-Giner, V. Lopez-Richard, Y. N\'u\~nez-Fern\'andez, Maurice   Oliva and Ming-Chiang Chung
cond-mat.quant-gas