  In this work, we investigated a Bose-Einstein condensate (BEC) inside a
Rydberg atom. We first observed the density profile of the system using the
Gross-Pitaevskii equation, and then we used the Bogoliubov theory to examine
the collective excitation spectra. We have also extended our study by taking
into account a hybrid of two BEC species. Again, for this new system, the
density profile and the collective excitation are investigated in a similar
manner. The results of the BEC for one species reveal that the Rydberg atom can
trap the BEC and that the excitation curve moves upward with increasing Rydberg
atom interaction. We have seen roton minima for two species of BEC, and the
depth of the minima shifts with the Rydberg interaction.
