  The low-energy excitations of filled Landau levels (LL's) of electrons
involve promotion of a single electron from the topmost filled LL to the lowest
empty LL. These are called excitons or collective modes. The incompressible
fractional quantum Hall states are understood as filled LL's of composite
fermions, and the low-energy neutral excitations are excitons of composite
fermions. New techniques are developed to study large systems, which provide
detailed information about the dispersions of the composite fermion excitons.
In particular, it is found that the interaction energy of the exciton is well
described by the `unprojected' composite fermion theory.
