  In two recent articles, Meiser and Meystre describe the coupled dynamics of a
dense gas of atoms and an optical cavity pumped by a laser field. They make two
important simplifying assumptions: (i) the gas of atoms forms a regular lattice
and can be replaced by a fictitious mirror, and (ii) the atoms strive to
minimize the dipole potential. We show that the two assumptions are
inconsistent: the configuration of atoms minimizing the dipole potential is not
a perfect lattice. Assumption (ii) is erroneous, as in the strong coupling
regime the dipole force does not arise from the dipole potential. The real
steady state, where the dipole forces vanish, is indeed a regular lattice.
Furthermore, the bistability predicted by Meiser and Meystre does not occur in
this system.
