  Quantum corrections to the energy of D0-branes in a constant RR 4-form
background are studied. Using the Born-Oppenheimer approximation, we compute
the long-range interaction between two spherical D2-D0 bound states. We extend
this calculation to the case where some mass terms are added. For the special
value of masses at which the classical energy vanishes, we find complete
cancellations of two boson-fermion pairs in the quantum mechanical expression
of the zero-point energy, suggesting possible restoration of (partial)
supersymmetries. We also briefly discuss the interaction between a dielectric
2-brane and a single D0-brane.
