For electrons in quantum dots the dipole absorption spectrum is known
to reflect only magnetoplasmon modes with a rigid center-of-mass motio
n (''generalized Kohn's theorem''). A more complex behavior is expecte
d for holes in quantum dots, as the valence-band mixing prohibits the
separation of relative and center-of-mass coordinates, and the dipole
field couples then also to the relative motion. We investigate theoret
ically the far-infrared response of hole-confining quantum dots, assum
ing a structure that can be realized by the lateral modulation of a tw
o-dimensional hole gas in a GaxAl1-xAs-GaAs quantum well or heterojunc
tion. The ground state of the many-hole system is determined in the lo
cal density approximation, using the 4x4 Luttinger Hamiltonian to incl
ude the valence-band mixing. The collective response to a dipole field
is calculated within the random phase approximation. The resulting fa
r-infrared absorption spectra exhibit a rich set of dipole active magn
etoplasmon modes with internal motions of the charge density, which du
e to the generalized Kohn's theorem are not possible for electrons in
quantum dots.